Method and apparatus for sl positioning reference signals

ABSTRACT

Methods and apparatuses for sidelink (SL) positioning reference signals (PRSs) in a wireless communication system. A method of operating a user equipment (UE) includes receiving configuration information for a SL resource pool. The SL resource pool is used for a SL PRS and control information associated with the SL PRS. The method further includes determining, based at least on the configuration information, resources for the SL PRS from the SL resource pool; transmitting the control information associated with the SL PRS; and transmitting the SL PRS on the determined resources.

CROSS-REFERENCE TO RELATED APPLICATIONS AND CLAIM OF PRIORITY

The present application claims priority to:

-   U.S. Provisional Patent Application No. 63/323,709, filed on Mar.     25, 2022; -   U.S. Provisional Patent Application No. 63/327,716, filed on Apr. 5,     2022; and -   U.S. Provisional Patent Application No. 63/445,944, filed on Feb.     15, 2023.

The contents of the above-identified patent document is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to wireless communication systems and, more specifically, the present disclosure relates to sidelink (SL) positioning reference signals (PRSs) in a wireless communication system.

BACKGROUND

5th generation (5G) or new radio (NR) mobile communications is recently gathering increased momentum with all the worldwide technical activities on the various candidate technologies from industry and academia. The candidate enablers for the 5G/NR mobile communications include massive antenna technologies, from legacy cellular frequency bands up to high frequencies, to provide beamforming gain and support increased capacity, new waveform (e.g., a new radio access technology (RAT)) to flexibly accommodate various services/applications with different requirements, new multiple access schemes to support massive connections, and so on.

SUMMARY

The present disclosure relates to wireless communication systems and, more specifically, the present disclosure relates to SL PRS in a wireless communication system.

In one embodiment, a user equipment (UE) is provided. The UE includes a transceiver configured to receive configuration information for a SL resource pool. The SL resource pool is used for a SL PRS and control information associated with the SL PRS. The UE further includes a processor operably coupled to the transceiver. The processor is configured to determine, based at least on the configuration information, resources for the SL PRS from the SL resource pool. The transceiver is further configured to transmit the control information associated with the SL PRS and transmit the SL PRS on the determined resources.

In another embodiment, another user equipment UE is provided. The UE includes a transceiver configured to receive configuration information for a SL resource pool. The SL resource pool is used for a SL PRS and control information associated with the SL PRS. The transceiver is further configured to receive the control information associated with the SL PRS and receive the SL PRS based on the control information. The UE further includes a processor operably coupled to the transceiver. The processor is configured to perform a positioning measurement based on the SL PRS and determine a positioning measurement report based on the positioning measurement. The transceiver is further configured to transmit the positioning measurement report.

In yet another embodiment, a method of operating a UE is provided. The method includes receiving configuration information for a SL resource pool. The SL resource pool is used for a SL PRS and control information associated with the SL PRS. The method further includes determining, based at least on the configuration information, resources for the SL PRS from the SL resource pool; transmitting the control information associated with the SL PRS; and transmitting the SL PRS on the determined resources.

Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims.

Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The term “couple” and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with one another. The terms “transmit,” “receive,” and “communicate,” as well as derivatives thereof, encompass both direct and indirect communication. The terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation. The term “or” is inclusive, meaning and/or. The phrase “associated with,” as well as derivatives thereof, means to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, or the like. The term “controller” means any device, system, or part thereof that controls at least one operation. Such a controller may be implemented in hardware or a combination of hardware and software and/or firmware. The functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. The phrase “at least one of,” when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one item in the list may be needed. For example, “at least one of: A, B, and C” includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C.

Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium. The terms “application” and “program” refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code. The phrase “computer readable program code” includes any type of computer code, including source code, object code, and executable code. The phrase “computer readable medium” includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A “non-transitory” computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device.

Definitions for other certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many if not most instances, such definitions apply to prior as well as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:

FIG. 1 illustrates an example of wireless network according to embodiments of the present disclosure;

FIG. 2 illustrates an example of gNB according to embodiments of the present disclosure;

FIG. 3 illustrates an example of UE according to embodiments of the present disclosure;

FIGS. 4 and 5 illustrate example of wireless transmit and receive paths according to the present disclosure;

FIG. 6A illustrates an example of overall positioning architecture along with positioning measurements according to embodiments of the present disclosure;

FIG. 6B illustrates an example location management function (LMF) according to embodiments of the present disclosure;

FIG. 7 illustrates an example of a UE in a network coverage according to embodiments of the present disclosure;

FIG. 8 illustrates a flowchart of a method for SL PRSs on a SL interface according to embodiments of the present disclosure;

FIG. 9 illustrates another flowchart of a method for SL PRSs on a SL interface according to embodiments of the present disclosure;

FIG. 10 illustrates an example of SL PRS in a slot according to embodiments of the present disclosure;

FIG. 11 illustrates an example of SL PRS transmission with an AGC symbol and a guard symbol according to embodiments of the present disclosure;

FIG. 12 illustrates an example of SL PRS transmission with configuration information and a guard symbol according to embodiments of the present disclosure;

FIG. 13 illustrates an example of time domain structure across slots according to embodiments of the present disclosure;

FIG. 14 illustrates an example of start of the frequency domain allocation for positioning according to embodiments of the present disclosure;

FIG. 15 illustrates an example of transmitted sub-carriers for SL PRS according to embodiments of the present disclosure;

FIG. 16 illustrates an example of control information associated with the reference signal for SL positioning measurements according to embodiments of the present disclosure;

FIGS. 17A-17H illustrate examples of time domain information according to embodiments of the present disclosure;

FIG. 18 illustrates an example of control information associated with the reference signal for SL positioning measurements according to embodiments of the present disclosure;

FIGS. 19A-19H illustrate examples of time domain information according to embodiments of the present disclosure;

FIG. 20 illustrates an example of control information associated with the reference signal for SL positioning measurements according to embodiments of the present disclosure;

FIG. 21 illustrates another example of control information associated with the reference signal for SL positioning measurements according to embodiments of the present disclosure; and

FIGS. 22A-22H illustrate examples of time domain information according to embodiments of the present disclosure.

DETAILED DESCRIPTION

FIG. 1 through FIG. 22H, discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device.

The following documents are hereby incorporated by reference into the present disclosure as if fully set forth herein: 3GPP TS 38.211 v17.0.0, “NR; Physical channels and modulation”; 3GPP TS 38.212 v17.0.0, “NR; Multiplexing and Channel coding”; 3GPP TS 38.213 v17.0.0, “NR; Physical Layer Procedures for Control”; 3GPP TS 38.214 v17.0.0, “NR; Physical Layer Procedures for Data”; 3GPP TS 38.215 v17.0.0, “NR; Physical Layer Measurements”; 3GPP TS 38.321 v16.7.0, “NR; Medium Access Control (MAC) protocol specification”; 3GPP TS 38.331 v16.7.0, “NR; Radio Resource Control (RRC) Protocol Specification”; 3GPP TS 36.213 v16.8.0, “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures”; and 3GPP TR 38.845 v17.0.0, “Study on scenarios and requirements of in-coverage, partial coverage, and out-of-coverage NR positioning use cases.”

To meet the demand for wireless data traffic having increased since deployment of 4G communication systems and to enable various vertical applications, 5G/NR communication systems have been developed and are currently being deployed. The 5G/NR communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 28 GHz or 60 GHz bands, so as to accomplish higher data rates or in lower frequency bands, such as 6 GHz, to enable robust coverage and mobility support. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G/NR communication systems.

In addition, in 5G/NR communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), reception-end interference cancelation, radio access technology (RAT)-dependent positioning and the like.

The discussion of 5G systems and frequency bands associated therewith is for reference as certain embodiments of the present disclosure may be implemented in 5G systems. However, the present disclosure is not limited to 5G systems, or the frequency bands associated therewith, and embodiments of the present disclosure may be utilized in connection with any frequency band. For example, aspects of the present disclosure may also be applied to deployment of 5G communication systems, 6G or even later releases which may use terahertz (THz) bands.

FIGS. 1-3 below describe various embodiments implemented in wireless communications systems and with the use of orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) communication techniques. The descriptions of FIGS. 1-3 are not meant to imply physical or architectural limitations to the manner in which different embodiments may be implemented. Different embodiments of the present disclosure may be implemented in any suitably arranged communications system.

FIG. 1 illustrates an example wireless network according to embodiments of the present disclosure. The embodiment of the wireless network shown in FIG. 1 is for illustration only. Other embodiments of the wireless network 100 could be used without departing from the scope of the present disclosure.

As shown in FIG. 1 , the wireless network includes a gNB 101 (e.g., base station, BS), a gNB 102, and a gNB 103. The gNB 101 communicates with the gNB 102 and the gNB 103. The gNB 101 also communicates with at least one network 130, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network.

The gNB 102 provides wireless broadband access to the network 130 for a first plurality of user equipments (UEs) within a coverage area 120 of the gNB 102. The first plurality of UEs includes a UE 111, which may be located in a small business; a UE 112, which may be located in an enterprise; a UE 113, which may be a WiFi hotspot; a UE 114, which may be located in a first residence; a UE 115, which may be located in a second residence; and a UE 116, which may be a mobile device, such as a cell phone, a wireless laptop, a wireless PDA, or the like. The gNB 103 provides wireless broadband access to the network 130 for a second plurality of UEs within a coverage area 125 of the gNB 103. The second plurality of UEs includes the UE 115 and the UE 116. In some embodiments, one or more of the gNBs 101-103 may communicate with each other and with the UEs 111-116 using 5G/NR, long term evolution (LTE), long term evolution-advanced (LTE-A), WiMAX, WiFi, or other wireless communication techniques.

In another example, the UE 116 may be within network coverage and the other UE may be outside network coverage (e.g., UEs 111A-111C). In yet another example, both UE are outside network coverage. In some embodiments, one or more of the gNBs 101-103 may communicate with each other and with the UEs 111-116 using 5G/NR, LTE, LTE-A, WiMAX, WiFi, or other wireless communication techniques. In some embodiments, the UEs 111-116 may use a device to device (D2D) interface called PC5 (e.g., also known as sidelink at the physical layer) for communication.

Depending on the network type, the term “base station” or “BS” can refer to any component (or collection of components) configured to provide wireless access to a network, such as transmit point (TP), transmit-receive point (TRP), an enhanced base station (eNodeB or eNB), a 5G/NR base station (gNB), a macrocell, a femtocell, a WiFi access point (AP), or other wirelessly enabled devices. Base stations may provide wireless access in accordance with one or more wireless communication protocols, e.g., 5G/NR 3rd generation partnership project (3GPP) NR, long term evolution (LTE), LTE advanced (LTE-A), high speed packet access (HSPA), Wi-Fi 802.11a/b/g/n/ac, etc. For the sake of convenience, the terms “BS” and “TRP” are used interchangeably in this patent document to refer to network infrastructure components that provide wireless access to remote terminals. Also, depending on the network type, the term “user equipment” or “UE” can refer to any component such as “mobile station,” “subscriber station,” “remote terminal,” “wireless terminal,” “receive point,” or “user device.” For the sake of convenience, the terms “user equipment” and “UE” are used in this patent document to refer to remote wireless equipment that wirelessly accesses a BS, whether the UE is a mobile device (such as a mobile telephone or smartphone) or is normally considered a stationary device (such as a desktop computer or vending machine).

Dotted lines show the approximate extents of the coverage areas 120 and 125, which are shown as approximately circular for the purposes of illustration and explanation only. It should be clearly understood that the coverage areas associated with gNBs, such as the coverage areas 120 and 125, may have other shapes, including irregular shapes, depending upon the configuration of the gNBs and variations in the radio environment associated with natural and man-made obstructions.

As described in more detail below, one or more of the UEs 111-116 include circuitry, programing, or a combination thereof, for sending and/or receiving SL PRSs in a wireless communication system. In certain embodiments, and one or more of the gNBs 101-103 includes circuitry, programing, or a combination thereof, to support configuration information for SL PRS in a wireless communication system.

Although FIG. 1 illustrates one example of a wireless network, various changes may be made to FIG. 1 . For example, the wireless network could include any number of gNBs and any number of UEs in any suitable arrangement. Also, the gNB 101 could communicate directly with any number of UEs and provide those UEs with wireless broadband access to the network 130. Similarly, each gNB 102-103 could communicate directly with the network 130 and provide UEs with direct wireless broadband access to the network 130. Further, the gNBs 101, 102, and/or 103 could provide access to other or additional external networks, such as external telephone networks or other types of data networks.

As discussed in greater detail below, the wireless network 100 may have communications facilitated via one or more devices (e.g., UEs 111A to 111C) that may have a SL communication with the UE 111. The UE 111 can communicate directly with the UEs 111A to 111C through a set of SLs (e.g., SL interfaces) to provide sideline communication, for example, in situations where the UEs 111A to 111C are remotely located or otherwise in need of facilitation for network access connections (e.g., BS 102) beyond or in addition to traditional fronthaul and/or backhaul connections/interfaces. In one example, the UE 111 can have direct communication, through the SL communication, with UEs 111A to 111C with or without support by the BS 102. Various of the UEs (e.g., as depicted by UEs 112 to 116) may be capable of one or more communication with their other UEs (such as UEs 111A to 111C as for UE 111).

FIG. 2 illustrates an example gNB 102 according to embodiments of the present disclosure. The embodiment of the gNB 102 illustrated in FIG. 2 is for illustration only, and the gNBs 101 and 103 of FIG. 1 could have the same or similar configuration. However, gNBs come in a wide variety of configurations, and FIG. 2 does not limit the scope of the present disclosure to any particular implementation of a gNB.

As shown in FIG. 2 , the gNB 102 includes multiple antennas 205 a-205 n, multiple transceivers 210 a-210 n, a controller/processor 225, a memory 230, and a backhaul or network interface 235.

The transceivers 210 a-210 n receive, from the antennas 205 a-205 n, incoming RF signals, such as signals transmitted by UEs in the network 100. The transceivers 210 a-210 n down-convert the incoming RF signals to generate IF or baseband signals. The IF or baseband signals are processed by receive (RX) processing circuitry in the transceivers 210 a-210 n and/or controller/processor 225, which generates processed baseband signals by filtering, decoding, and/or digitizing the baseband or IF signals. The controller/processor 225 may further process the baseband signals.

Transmit (TX) processing circuitry in the transceivers 210 a-210 n and/or controller/processor 225 receives analog or digital data (such as voice data, web data, e-mail, or interactive video game data) from the controller/processor 225. The TX processing circuitry encodes, multiplexes, and/or digitizes the outgoing baseband data to generate processed baseband or IF signals. The transceivers 210 a-210 n up-converts the baseband or IF signals to RF signals that are transmitted via the antennas 205 a-205 n.

The controller/processor 225 can include one or more processors or other processing devices that control the overall operation of the gNB 102. For example, the controller/processor 225 could control the reception of UL channel signals and the transmission of DL channel signals by the transceivers 210 a-210 n in accordance with well-known principles. The controller/processor 225 could support additional functions as well, such as more advanced wireless communication functions. For instance, the controller/processor 225 could support beam forming or directional routing operations in which outgoing/incoming signals from/to multiple antennas 205 a-205 n are weighted differently to effectively steer the outgoing signals in a desired direction. Any of a wide variety of other functions could be supported in the gNB 102 by the controller/processor 225.

The controller/processor 225 is also capable of executing programs and other processes resident in the memory 230, such as an OS. The controller/processor 225 can move data into or out of the memory 230 as required by an executing process. The controller/processor 225 is also capable of executing programs and other processes resident in the memory 230, such as processes to provide or support control information for SL PRSs in a wireless communication system.

The controller/processor 225 is also coupled to the backhaul or network interface 235. The backhaul or network interface 235 allows the gNB 102 to communicate with other devices or systems over a backhaul connection or over a network. The interface 235 could support communications over any suitable wired or wireless connection(s). For example, when the gNB 102 is implemented as part of a cellular communication system (such as one supporting 5G/NR, LTE, or LTE-A), the interface 235 could allow the gNB 102 to communicate with other gNBs over a wired or wireless backhaul connection. When the gNB 102 is implemented as an access point, the interface 235 could allow the gNB 102 to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the Internet). The interface 235 includes any suitable structure supporting communications over a wired or wireless connection, such as an Ethernet or transceiver.

The memory 230 is coupled to the controller/processor 225. Part of the memory 230 could include a RAM, and another part of the memory 230 could include a Flash memory or other ROM.

Although FIG. 2 illustrates one example of gNB 102, various changes may be made to FIG. 2 . For example, the gNB 102 could include any number of each component shown in FIG. 2 . Also, various components in FIG. 2 could be combined, further subdivided, or omitted and additional components could be added according to particular needs.

FIG. 3 illustrates an example UE 116 according to embodiments of the present disclosure. The embodiment of the UE 116 illustrated in FIG. 3 is for illustration only, and the UEs 111-115 of FIG. 1 could have the same or similar configuration. However, UEs come in a wide variety of configurations, and FIG. 3 does not limit the scope of the present disclosure to any particular implementation of a UE.

As shown in FIG. 3 , the UE 116 includes antenna(s) 305, a transceiver(s) 310, and a microphone 320. The UE 116 also includes a speaker 330, a processor 340, an input/output (I/O) interface (IF) 345, an input 350, a display 355, and a memory 360. The memory 360 includes an operating system (OS) 361 and one or more applications 362.

The transceiver(s) 310 receives, from the antenna 305, an incoming RF signal transmitted by a gNB of the network 100 or by other UEs (e.g., one or more of UEs 111-115) on a SL channel. The transceiver(s) 310 down-converts the incoming RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is processed by RX processing circuitry in the transceiver(s) 310 and/or processor 340, which generates a processed baseband signal by filtering, decoding, and/or digitizing the baseband or IF signal. The RX processing circuitry sends the processed baseband signal to the speaker 330 (such as for voice data) or is processed by the processor 340 (such as for web browsing data).

TX processing circuitry in the transceiver(s) 310 and/or processor 340 receives analog or digital voice data from the microphone 320 or other outgoing baseband data (such as web data, e-mail, or interactive video game data) from the processor 340. The TX processing circuitry encodes, multiplexes, and/or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The transceiver(s) 310 up-converts the baseband or IF signal to an RF signal that is transmitted via the antenna(s) 305.

The processor 340 can include one or more processors or other processing devices and execute the OS 361 stored in the memory 360 in order to control the overall operation of the UE 116. For example, the processor 340 could control the reception of DL and/or SL channels and/or signals and the transmission of UL and/or SL channels and/or signals by the transceiver(s) 310 in accordance with well-known principles. In some embodiments, the processor 340 includes at least one microprocessor or microcontroller.

The processor 340 is also capable of executing other processes and programs resident in the memory 360, such as processes for SL PRSs in a wireless communication system. The processor 340 can move data into or out of the memory 360 as required by an executing process. In some embodiments, the processor 340 is configured to execute the applications 362 based on the OS 361 or in response to signals received from gNBs or an operator. The processor 340 is also coupled to the I/O interface 345, which provides the UE 116 with the ability to connect to other devices, such as laptop computers and handheld computers. The I/O interface 345 is the communication path between these accessories and the processor 340.

The processor 340 is also coupled to the input 350, which includes for example, a touchscreen, keypad, etc., and the display 355. The operator of the UE 116 can use the input 350 to enter data into the UE 116. The display 355 may be a liquid crystal display, light emitting diode display, or other display capable of rendering text and/or at least limited graphics, such as from web sites.

The memory 360 is coupled to the processor 340. Part of the memory 360 could include a random-access memory (RAM), and another part of the memory 360 could include a Flash memory or other read-only memory (ROM).

Although FIG. 3 illustrates one example of UE 116, various changes may be made to FIG. 3 . For example, various components in FIG. 3 could be combined, further subdivided, or omitted and additional components could be added according to particular needs. As a particular example, the processor 340 could be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). In another example, the transceiver(s) 310 may include any number of transceivers and signal processing chains and may be connected to any number of antennas. Also, while FIG. 3 illustrates the UE 116 configured as a mobile telephone or smartphone, UEs could be configured to operate as other types of mobile or stationary devices.

FIG. 4 and FIG. 5 illustrate example wireless transmit and receive paths according to the present disclosure. In the following description, a transmit path 400 may be described as being implemented in a gNB (such as the gNB 102), while a receive path 500 may be described as being implemented in a UE (such as a UE 116). However, it may be understood that the receive path 500 can be implemented in a gNB and that the transmit path 400 can be implemented in a UE. It may also be understood that the receive path 500 can be implemented in a first UE and that the transmit path 400 can be implemented in a second UE to support SL communications and/or SL positioning. In some embodiments, the receive path 500 is configured to support the SL PRS techniques as described in embodiments of the present disclosure.

The transmit path 400 as illustrated in FIG. 4 includes a channel coding and modulation block 405, a serial-to-parallel (S-to-P) block 410, a size N inverse fast Fourier transform (IFFT) block 415, a parallel-to-serial (P-to-S) block 420, an add cyclic prefix block 425, and an up-converter (UC) 430. The receive path 500 as illustrated in FIG. 5 includes a down-converter (DC) 555, a remove cyclic prefix block 560, a serial-to-parallel (S-to-P) block 565, a size N fast Fourier transform (FFT) block 570, a parallel-to-serial (P-to-S) block 575, and a channel decoding and demodulation block 580.

As illustrated in FIG. 4 , the channel coding and modulation block 405 receives a set of information bits, applies coding (such as a low-density parity check (LDPC) coding), and modulates the input bits (such as with quadrature phase shift keying (QPSK) or quadrature amplitude modulation (QAM)) to generate a sequence of frequency-domain modulation symbols.

The serial-to-parallel block 410 converts (such as de-multiplexes) the serial modulated symbols to parallel data in order to generate N parallel symbol streams, where N is the IFFT/FFT size used in the gNB 102 and the UE 116. The size N IFFT block 415 performs an IFFT operation on the N parallel symbol streams to generate time-domain output signals. The parallel-to-serial block 420 converts (such as multiplexes) the parallel time-domain output symbols from the size N IFFT block 415 in order to generate a serial time-domain signal. The add cyclic prefix block 425 inserts a cyclic prefix to the time-domain signal. The up-converter 430 modulates (such as up-converts) the output of the add cyclic prefix block 425 to an RF frequency for transmission via a wireless channel. The signal may also be filtered at baseband before conversion to the RF frequency.

A transmitted RF signal from the gNB 102 arrives at the UE 116 after passing through the wireless channel, and reverse operations to those at the gNB 102 are performed at the UE 116. In the example where the UE 111 has direct communication, through the SL communication, with UEs 111A to 111C with or without support by the BS 102, a transmitted RF signal from a first UE arrives at a second UE after passing through the wireless channel, and reverse operations to those at the first UE are performed at the second UE.

As illustrated in FIG. 5 , the downconverter 555 down-converts the received signal to a baseband frequency, and the remove cyclic prefix block 560 removes the cyclic prefix to generate a serial time-domain baseband signal. The serial-to-parallel block 565 converts the time-domain baseband signal to parallel time domain signals. The size N FFT block 570 performs an FFT algorithm to generate N parallel frequency-domain signals. The parallel-to-serial block 575 converts the parallel frequency-domain signals to a sequence of modulated data symbols. The channel decoding and demodulation block 580 demodulates and decodes the modulated symbols to recover the original input data stream.

Each of the gNB s 101-103 may implement a transmit path 400 as illustrated in FIG. 4 that is analogous to transmitting in the downlink to UEs 111-116 and may implement a receive path 500 as illustrated in FIG. 5 that is analogous to receiving in the uplink from UEs 111-116. Similarly, each of UEs 111-116 may implement the transmit path 400 for transmitting in the uplink to the gNBs 101-103 and/or transmitting in the sidelink to another UE and may implement the receive path 500 for receiving in the downlink from the gNBs 101-103 and/or receiving in the sidelink from another UE.

Each of the components in FIG. 4 and FIG. 5 can be implemented using only hardware or using a combination of hardware and software/firmware. As a particular example, at least some of the components in FIG. 4 and FIG. 5 may be implemented in software, while other components may be implemented by configurable hardware or a mixture of software and configurable hardware. For instance, the FFT block 570 and the IFFT block 415 may be implemented as configurable software algorithms, where the value of size N may be modified according to the implementation.

Furthermore, although described as using FFT and IFFT, this is by way of illustration only and may not be construed to limit the scope of the present disclosure. Other types of transforms, such as discrete Fourier transform (DFT) and inverse discrete Fourier transform (IDFT) functions, can be used. It may be appreciated that the value of the variable N may be any integer number (such as 1, 2, 3, 4, or the like) for DFT and IDFT functions, while the value of the variable N may be any integer number that is a power of two (such as 1, 2, 4, 8, 16, or the like) for FFT and IFFT functions.

Although FIG. 4 and FIG. 5 illustrate examples of wireless transmit and receive paths, various changes may be made to FIG. 4 and FIG. 5 . For example, various components in FIG. 4 and FIG. 5 can be combined, further subdivided, or omitted and additional components can be added according to particular needs. Also, FIG. 4 and FIG. 5 are meant to illustrate examples of the types of transmit and receive paths that can be used in a wireless network. Any other suitable architectures can be used to support wireless communications in a wireless network.

A time unit for DL signaling, for UL signaling, or for SL signaling on a cell is one symbol. A symbol belongs to a slot that includes a number of symbols such as 14 symbols. A slot can also be used as a time unit. A bandwidth (BW) unit is referred to as a resource block (RB). One RB includes a number of sub-carriers (SCs).

For example, a slot can have duration of one millisecond and an RB can have a bandwidth of 180 kHz and include 12 SCs with inter-SC spacing of 15 kHz. As another example, a slot can have a duration of 0.25 milliseconds and include 14 symbols and an RB can have a BW of 720 kHz and include 12 SCs with SC spacing of 60 kHz. An RB in one symbol of a slot is referred to as physical RB (PRB) and includes a number of resource elements (REs). A slot can be either full DL slot, or full UL slot, or hybrid slot similar to a special subframe in time division duplex (TDD) systems. In addition, a slot can have symbols for SL communications. A UE can be configured one or more bandwidth parts (BWPs) of a system BW for transmissions or receptions of signals or channels.

NR supports positioning on the Uu interface. In the DL, PRS can be transmitted by a gNB to a UE to enable the UE to perform positioning measurements. In the UL, a UE can transmit positioning sounding reference signal (SRS) to enable a gNB to perform positioning measurements. UE measurements for positioning include; DL PRS reference signal received power (DL PRS RSRP), DL PRS reference signal received path power (DL PRS-RSRPP), DL reference signal time difference (DL RSTD), UE Rx-Tx time difference, NR enhanced cell ID (E-CID), DL SSB radio resource management (RRM) measurement, and NR E-CID DL CSI-RS RRM measurement. NG-RAN measurements for positioning include; UL relative time of arrival (UL-RTOA), UL angle of arrival (UL AoA), UL SRS reference signal received power (UL SRS-RSRP), UL SRS reference signal received path power (UL SRS-RSRPP) and gNB Rx-Tx time difference.

NR introduced several radio access technology (RAT) dependent positioning methods; time difference of arrival based methods such DL time difference of arrival (DL-TDOA) and UL time difference of arrival (UL TDOA), angle based methods such as UL angle of arrival (UL AoA) and DL angle of departure (DL AoD), multi-round trip time (RTT) based methods and E-CID based methods.

Positioning schemes can be UE-based, i.e., the UE determines the location or UE-assisted (e.g., location management function (LMF) based), i.e., UE provides measurements for a network entity (e.g., LMF) to determine the location, or NG-RAN node assisted (i.e., NG-RAN node such as gNB provides measurement to LMF). LTE positioning protocol (LPP), as illustrated in 3GPP TS 37.355, first introduces for LTE and then extended to NR is used for communication between the UE and LMF. NR positioning protocol annex (NRPPa), as illustrated in 3GPP TS 38.455, is used for communication between the gNB and the LMF.

FIG. 6A illustrates an example of overall positioning architecture along with positioning measurements 600 according to embodiments of the present disclosure. An embodiment of the overall positioning architecture along with positioning measurements 600 shown in FIG. 6A is for illustration only.

FIG. 6B illustrates an example LMF 650 according to embodiments of the present disclosure. The embodiment of the LMF 650 shown in FIG. 6B is for illustration only. However, LMFs come in a wide variety of configurations, and FIG. 6B does not limit the scope of this disclosure to any particular implementation of an LMF.

As shown in FIG. 6B, the LMF 650 includes a controller/processor 655, a memory 660, and a backhaul or network interface 665. The controller/processor 655 can include one or more processors or other processing devices that control the overall operation of the LMF 650. For example, the controller/processor can support functions related to positioning and location services. Any of a wide variety of other functions can be supported in the LMF 650 by the controller/processor 655. In some embodiments, the controller/processor 655 includes at least one microprocessor or microcontroller.

The controller/processor 655 is also capable of executing programs and other processes resident in the memory 660, such as a basic OS. In some embodiments, the controller/processor 655 supports communications between entities, such as gNB 102 and UE 116 and supports protocols such as LPP and NRPPA. The controller/processor 655 can move data into or out of the memory 660 as required by an executing process.

The controller/processor 655 is also coupled to the backhaul or network interface 665. The backhaul or network interface 665 allows the LMF 650 to communicate with other devices or systems over a backhaul connection or over a network. The interface 665 can support communications over any suitable wired or wireless connection(s). For example, when the LMF 650 is implemented as part of a cellular communication system or wired or wireless local area network (such as one supporting 5G, LTE, or LTE-A), the interface 665 can allow the LMF 650 to communicate with gNBs or eNBs or other network elements over a wired or wireless backhaul connection. The interface 665 includes any suitable structure supporting communications over a wired or wireless connection, such as an Ethernet or RF transceiver.

The memory 660 is coupled to the controller/processor 655. Part of the memory 660 can include a RAM, and another part of the memory 660 can include a Flash memory or other ROM. In certain embodiments, a plurality of instructions, such as for location management is stored in memory 660. The plurality of instructions is configured to cause the controller/processor 655 to perform for location management process and to perform positioning or location services algorithms.

SL signals and channels are transmitted and received on sub-channels within a resource pool, where a resource pool is a set of time-frequency resources used for SL transmission and reception within a SL BWP. SL channels include physical SL shared channels (PSSCHs) conveying data information and second stage/part SL control information (SCI), physical SL control channels (PSCCHs) conveying first stage/part SCI for scheduling transmissions/receptions of PSSCHs, physical SL feedback channels (PSFCHs) conveying hybrid automatic repeat request acknowledgement (HARQ-ACK) information in response to correct (ACK value) or incorrect (NACK value) transport block receptions in respective PSSCHs, and physical SL Broadcast channel (PSBCH) conveying system information to assist in SL synchronization.

SL signals include demodulation reference signals DM-RS that are multiplexed in PSSCH or PSCCH transmissions to assist with data or SCI demodulation, channel state information reference signals (CSI-RS) for channel measurements, phase tracking reference signals (PT-RS) for tracking a carrier phase, and SL primary synchronization signals (S-PSS) and SL secondary synchronization signals (S-SSS) for SL synchronization. SCI can include two parts/stages corresponding to two respective SCI formats where, for example, the first SCI format is multiplexed on a PSCCH and the second SCI format is multiplexed along with SL data on a PSSCH that is transmitted in physical resources indicated by the first SCI format.

A SL channel can operate in different cast modes. In a unicast mode, a PSCCH/PSSCH conveys SL information from one UE to only one other UE. In a groupcast mode, a PSCCH/PSSCH conveys SL information from one UE to a group of UEs within a (pre-)configured set. In a broadcast mode, a PSCCH/PSSCH conveys SL information from one UE to all surrounding UEs. In NR release 16, there are two resource allocation modes for a PSCCH/PSSCH transmission. In resource allocation mode 1, a gNB schedules a UE on the SL and conveys scheduling information to the UE transmitting on the SL through a DCI format (e.g., DCI Format 3_0). In resource allocation mode 2, a UE schedules a SL transmission. SL transmissions can operate within network coverage where each UE is within the communication range of a gNB, outside network coverage where all UEs have no communication with any gNB, or with partial network coverage, where only some UEs are within the communication range of a gNB.

In case of groupcast PSCCH/PSSCH transmission, a UE can be (pre-)configured one of two options for reporting of HARQ-ACK information by the UE as shown in below examples.

In one example of HARQ-ACK reporting option (1), a UE can attempt to decode a transport block (TB) in a PSSCH reception if, for example, the UE detects a SCI format scheduling the TB reception through a corresponding PSSCH. If the UE fails to correctly decode the TB, the UE multiplexes a negative acknowledgement (NACK) in a PSFCH transmission. In this option, the UE does not transmit a PSFCH with a positive acknowledgment (ACK) when the UE correctly decodes the TB.

In one example of HARQ-ACK reporting option (2), a UE can attempt to decode a TB if, for example, the UE detects a SCI format that schedules a corresponding PSSCH. If the UE correctly decodes the TB, the UE multiplexes an ACK in a PSFCH transmission; otherwise, if the UE does not correctly decode the TB, the UE multiplexes a NACK in a PSFCH transmission.

In HARQ-ACK reporting option (1), when a UE that transmitted the PSSCH detects a NACK in a PSFCH reception, the UE can transmit another PSSCH with the TB (retransmission of the TB). In HARQ-ACK reporting option (2) when a UE that transmitted the PSSCH does not detect an ACK in a PSFCH reception, such as when the UE detects a NACK or does not detect a PSFCH reception, the UE can transmit another PSSCH with the TB.

A sidelink resource pool includes a set/pool of slots and a set/pool of RBs used for sidelink transmission and sidelink reception. A set of slots which belong to a sidelink resource pool can be denoted by {t′₀ ^(SL), t′₁ ^(SL), t′₂ ^(SL), . . . , t′_(T′) _(MAX) ₋₁ ^(SL)} and can be configured, for example, at least using a bitmap. Where, T′_(MAX) is the number of SL slots in a resource pool in 1024 frames. Within each slot t′_(y) ^(SL) of a sidelink resource pool, there are N_(subCH) contiguous sub channels in the frequency domain for sidelink transmission, where N_(subCH) is provided by a higher-layer parameter. Subchannel m, where m is between 0 and N_(subCH)−1, is given by a set of n_(subCHsize) contiguous PRBs, given by n_(PRB)=n_(subCHstart)+m·n_(subCHsize)+j, where j=0, 1, . . . , n_(subCHsize)−1, n_(subCHstart) and n_(subCHsize) are provided by higher layer parameters.

For resource (re-)selection or re-evaluation in slot n, a UE can determine a set of available single-slot resources for transmission within a resource selection window [n+T₁, n+T₂], such that a single-slot resource for transmission, R_(x,y) is defined as a set of L_(subCH) contiguous subchannels x+i, where i=0, 1, . . . , L_(subCH)−1 in slot t_(y) ^(SL). T₁ is determined by the UE such that, 0≤T₁≤T_(proc,1) ^(SL), where T_(proc,1) ^(SL) is a PSSCH processing time for example as defined in 3GPP standard specification (TS 38.214). T₂ is determined by the UE such that T_(2min)≤T₂≤Remaining Packet Delay Budget, as long as T_(2min)<Remaining Packet Delay Budget, else T₂ is equal to the Remaining Packet Delay Budget. T_(2min) is a configured by higher layers and depends on the priority of the SL transmission.

The slots of a SL resource pool are determined as shown in TABLE 1.

TABLE 1 Slots of a SL resource pool 1. Let set of slots that may belong to a resource be denoted by {t₀ ^(SL), t₁ ^(SL), t₂ ^(SL), . . . ,  t_(T) _(MAX) ⁻¹ ^(SL)},  where 0 ≤ t_(i) ^(SL) < 10240 × 2^(μ), and 0 ≤ i <T_(max) . μ is the sub-carrier spacing  configuration. μ = 0 for a 15 kHz sub-carrier spacing. μ = 1 for a 30 kHz sub-carrier  spacing. μ = 2 for a 60 KHz sub-carrier spacing. μ = 3 for a 120 kHz sub-carrier  spacing. The slot index is relative to slot#0 of SFN#0 (system frame number 0) of the  serving cell, or DFN#0 (direct frame number 0). The set of slots includes all slots except:   a. N_(S−SSB) slots that are configured for SL SS/PBCH Block (S-SSB).   b. N_(nonSL), slots where at least one SL symbol is not not-semi-statically configured    as UL symbol by higher layer parameter tdd-UL-DL-ConfigurationCommon or    sl-TDD-Configurauion. In a SL slot, OFDM symbols Y-th, (Y+1)-th, . . . , (Y+X-    1)-th are SL symbols, where Y is determined by the higher layer parameter sl-    StartSymbol and X is determined by higher layer parameter sl-LengthSymbols.   c. N_(reserved) reserved slots. Reserved slots are determined such that the slots in the    set {t₀ ^(SL), t₁ ^(SL), t₂ ^(SL), . . . , t_(T) _(MAX) ⁻¹ ^(SL)} is a multiple of the bitmap length (L_(bitmap)),    where the bitmap (b₀, b₁, . . . , b_(L) _(bitmap) ⁻¹) is configured by higher layers. The    reserved slots are determined as follows:     i. Let {l₀, l₁, . . . , l₂ _(μ) _(×10240−N) _(S−SSB) _(−N) _(nonSL) ⁻¹} be the set of slots in range 0 . . .      2^(μ) × 10240 − 1, excluding S-SSB slots and non-SL slots. The slots are      arranged in ascending order of the slot index.     ii. The number of reserved slots is given by: N_(reserved) = (2^(μ) × 10240 −      N_(S−SSB) − N_(nonSL)) mod L_(bitmap).     iii. The reserved slots l_(r) are given by: ${r = \left\lfloor \frac{m \cdot \left( {{2^{\mu} \times 10240} - N_{S - {SSB}} - N_{nonSL}} \right)}{N_{reserved}} \right\rfloor},$      where m = 0, 1, . . . , N_(reserved) − 1  T_(max) is given by: T_(max) = 2^(μ) × 10240 − N_(S−SSB) − N_(nonSL) − N_(reserved). 2. The slots are arranged in ascending order of slot index. 3. The set of slots belonging to the SL resource pool, {t′₀ ^(SL), t′₁ ^(SL) t′₂ ^(SL), . . . , t′_(T′) _(MAX) ⁻¹ ^(SL)},  are determined as follows:   a. Each resource pool has a corresponding bitmap (b₀, b₁, . . . , b_(L) _(bitmap) ⁻¹) of length    L_(bitmap).   b. A slot t_(k) ^(SL) belongs to the SL resource pool if b_(k mod L) _(bitmap) = 1   c. The remaining slots are indexed successively staring from 0, 1, . . . T′_(MAX) − 1.    Where, T′_(MAX) is the number of remaining slots in the set.

Slots can be numbered (indexed) as physical slots or logical slots, wherein physical slots include all slots numbered sequential, while logical slots include only slots that can be allocated to sidelink resource pool as described above numbered sequentially. The conversion from a physical duration, P_(rsvp), in milli-second to logical slots, P′_(rsvp), is given by

$P_{rsvp}^{\prime} = \left\lceil {\frac{{{T}^{\prime}}_{\max}}{10240{ms}} \times P_{rsvp}} \right\rceil$

(see 3GPP standard specification 38.214).

For resource (re-)selection or re-evaluation in slot n, a UE can determine a set of available single-slot resources for transmission within a resource selection window [n+T₁, n+T₂], such that a single-slot resource for transmission, R_(x,y) is defined as a set of L_(subCH) contiguous subchannels x+i, where i=0, 1, . . . , L_(subCH)−1 in slot t_(y) ^(SL). T₁ is determined by the UE such that, 0≤T₁≤T_(proc,1) ^(SL), where T_(proc,1) ^(SL) is a PSSCH processing time for example as defined in 3GPP standard specification (TS 38.214). T₂ is determined by the UE such that T_(2min)≤T₂≤Remaining Packet Delay Budget, as long as T_(2min)<Remaining Packet Delay Budget, else T₂ is equal to the Remaining Packet Delay Budget. T_(2min) is configured by higher layers and depends on the priority of the SL transmission.

The resource (re-)selection is a two-step procedure: (1) the first step (e.g., performed in the physical layer) is to identify the candidate resources within a resource selection window. Candidate resources are resources that belong to a resource pool, but exclude resources (e.g., resource exclusion) that were previously reserved, or potentially reserved by other UEs. The resources excluded are based on SCIs decoded in a sensing window and for which the UE measures a SL RSRP that exceeds a threshold. The threshold depends on the priority indicated in a SCI format and on the priority of the SL transmission. Therefore, sensing within a sensing window involves decoding the first stage SCI, and measuring the corresponding SL RSRP, wherein the SL RSRP can be based on PSCCH DMRS or PSSCH DMRS. Sensing is performed over slots where the UE doesn't transmit SL. The resources excluded are based on reserved transmissions or semi-persistent transmissions that can collide with the excluded resources or any of reserved or semi-persistent transmissions; the identified candidate resources after resource exclusion are provided to higher layers and (2) the second step (e.g., preformed in the higher layers) is to select or re-select a resource from the identified candidate resources.

During the first step of the resource (re-)selection procedure, a UE can monitor slots in a sensing window [n−T₀, n−T_(proc,0)), where the UE monitors slots belonging to a corresponding sidelink resource pool that are not used for the UE's own transmission. To determine a candidate single-slot resource set to report to higher layers, a UE excludes (e.g., resource exclusion) from the set of available single-slot resources for SL transmission within a resource pool and within a resource selection window, as shown in TABLE 2.

TABLE 2 Slot resources for SL transmission 1. Single slot resource R_(x,y), such that for any slot t′_(m) ^(SL) not monitored within the sensing  window with a hypothetical received SCI Format 1-0, with a “Resource reservation  period” set to any periodicity value allowed by a higher layer parameter  reseverationPeriodAllowed, and indicating all sub-channels of the resource pool in this  slot, satisfies condition 2.2. below. 2. Single slot resource R_(x,y), such that for any received SCI within the sensing window:   1. The associated L1-RSRP measurement is above a (pre-)configured SL-RSRP    threshold, where the SL-RSRP threshold depends on the priority indicated in the    received SCI and that of the SL transmission for which resources are being    selected.   2. (Condition 2.2) The received SCI in slot t′_(m) ^(SL) or if “Resource reservation field”    is present in the received SCI the same SCI is assumed to be received in slot    t′_(m+q×P′) _(rsvp) _Rx^(SL), indicates a set of resource blocks that overlaps R_(x,y+j×P′) _(rsvp) _Tx.    Where,     • q = 1,2, . . . , Q, where,     • If P_(rsvp)_RX ≤ T_(scal) and n' − m < P′_(rsvp)_Rx → $Q = {\left\lceil \frac{T_{scal}}{P_{rsvp\_ RX}} \right\rceil.T_{scal}}$      is T₂ in units of milli-seconds.     • Else Q = 1     • If n belongs to (t′₀ ^(SL), t′₁ ^(SL) , . . . , t′_(T′) _(MAX) ⁻¹ ^(SL)), n′ = n, else n′ is the      first slot after slot n belonging to set (t′₀ ^(SL), t′₁ ^(SL), . . . , t′_(T′) _(MAX) ⁻¹ ^(SL)).     • j = 0,1, . . . , C_(resel) − 1     • P_(rsvp)_RX is the indicated resource reservation period in the received SCI      in physical slots, and P′_(rsvp)_Rx is that value converted to logical slots.     • P′_(rsvp)_Rx is the resource reservation period of the SL transmissions for      which resources are being reserved in logical slots. 3. If the candidate resources are less than a (pre-)configured percentage, such as 20%, of  the total available resources within the resource selection window, the (pre-)configured  SL-RSRP thresholds are increased by a predetermined amount, such as 3 dB.

NR sidelink introduced two new procedures for mode 2 resource allocation; re-evaluation and pre-emption.

Re-evaluation check occurs when a UE checks the availability of pre-selected SL resources before the resources are first signaled in an SCI Format, and if needed re-selects new SL resources. For a pre-selected resource to be first-time signaled in slot m, the UE performs a re-evaluation check at least in slot m−T₃.

The re-evaluation check includes: (1) performing the first step of the SL resource selection procedure (e.g., 3GPP standard specification 38.214), which involves identifying a candidate (available) sidelink resource set in a resource selection window as previously described; (2) if the pre-selected resource is available in the candidate sidelink resource set, the resource is used/signaled for sidelink transmission; and (3) else, the pre-selected resource is not available in the candidate sidelink resource set, a new sidelink resource is re-selected from the candidate sidelink resource set.

A pre-emption check occurs when a UE checks the availability of pre-selected SL resources that have been previously signaled and reserved in an SCI Format, and if needed re-selects new SL resources. For a pre-selected and reserved resource to be signaled in slot m, the UE performs a pre-emption check at least in slot m−T₃.

When pre-emption check is enabled by higher layers, pre-emption check includes: (1) performing the first step of the SL resource selection procedure (e.g., 3GPP standard specification 38.214), which involves identifying candidate (available) sidelink resource set in a resource selection window as previously described; (1) if the pre-selected and reserved resource is available in the candidate sidelink resource set, the resource is used/signaled for sidelink transmission; and (3) else, the pre-selected and reserved resource is NOT available in the candidate sidelink resource set. The resource is excluded from the candidate resource set due to an SCI, associated with a priority value P_(RX), having an RSRP exceeding a threshold. Let the priority value of the sidelink resource being checked for pre-emption be P_(TX).

In such instances, (1) if the priority value P_(RX) is less than a higher-layer configured threshold and the priority value P_(RX) is less than the priority value P_(TX). The pre-selected and reserved sidelink resource is pre-empted. A new sidelink resource is re-selected from the candidate sidelink resource set. Note that, a lower priority value indicates traffic of higher priority; and (2) else, the resource is used/signaled for sidelink transmission.

The positioning solutions provided for release 16 target the following commercial requirements for commercial applications.

TABLE 3 Positioning solutions Requirement characteristic Requirement target Horizontal Positioning Error Indoor: 3 m for 80% of the UEs Outdoor: 10 m for 80% of the UEs Vertical Positioning Error Indoor: 3 m for 80% of the UEs Outdoor: 3 m for 80% of the UEs End to end latency Less than 1 second

To meet these requirements, radio access technology (RAT)-dependent, RAT independent, and a combination of RAT-dependent and RAT independent positioning schemes have been considered. For the RAT-dependent positioning schemes, timing based positioning schemes as well as angle-based positioning schemes have been considered. For timing based positioning schemes, NR supports DL time difference of arrival (DL-TDOA), using PRSs for time of arrival measurements. NR also supports UL time difference of arrival (UL-TDOA), using sounding reference signals (SRS) for time of arrival measurements.

NR also supports round-trip time (RTT) with one or more neighboring gNBs or transmission/reception points (TRPs). For angle based positioning schemes, NR exploits the beam-based air interface, supporting downlink angle of departure (DL-AoD), as well as uplink angle of arrival (UL-AoA). Furthermore, NR supports enhanced cell-ID (E-CID) based positioning schemes. RAT independent positioning schemes can be based on global navigation satellite systems (GNSS), WLAN (e.g., WiFi), Bluetooth, terrestrial beacon system (TBS), as well as sensors within the UE such as accelerometers, gyroscopes, magnetometers, etc. Some of the UE sensors are also known as inertial measurement unit (IMU).

As NR expands into new verticals, there is a need to provide improved and enhanced location capabilities to meet various regulatory and commercial positioning requirements. 3GPP SA1 considered the service requirements for high accuracy positioning in TS 22.261 and identified seven service levels for positioning, with varying levels of accuracy (horizontal accuracy and vertical accuracy), positioning availability, latency requirement, as well as positioning type (absolute or relative).

One of the positioning service levels is relative positioning (see table 3GPP standard specification TS 22.261), with a horizontal and vertical accuracy of 0.2 m, availability of 99%, latency of 1 sec, and targeting indoor and outdoor environments with speed up to 30 km/hr and distance between UEs or a UE and a 5G positioning node of 10 m.

Rel-17 further enhanced the accuracy, latency, reliability and efficiency of positioning schemes for commercial and IIoT applications. Targeting to achieve sub-meter accuracy with a target latency less than 100 ms for commercial applications, and accuracy better than 20 cm with a target latency in the order of 10 ms for IIoT applications.

In Rel-17, RAN undertook a study item for in-coverage, partial coverage and out-of-coverage NR positioning use cases. The study focused on identifying positioning use cases and requirements for V2X and public safety as well as identifying potential deployment and operation scenarios. The outcome of the study item is included in TR 38.845. V2X positioning requirements depend on the service the UE operates, and are applicable to absolute and relative positioning. Use cases include indoor, outdoor and tunnel areas, within network coverage or out of network coverage; as well as with GNSS-based positioning available, or not available, or not accurate enough; and with UE speeds up to 250 km/h. There are three sets of requirements for V2X use cases; the first with horizontal accuracy in the 10 to 50 m range, the second with horizontal accuracy in the 1 to 3 m range, and the third with horizontal accuracy in the 0.1 to 0.5 m range.

The 5G system can also support determining the velocity of a UE with a speed accuracy better that 0.5 m/s and a 3-Dimension direction accuracy better than 5 degrees. Public safety positioning is to support indoor and outdoor use cases, with in network coverage or out of network coverage; as well as with GNSS-based positioning available, or not available, or not accurate enough. Public safety positioning use cases target a 1-meter horizontal accuracy and a vertical accuracy of 2 m (absolute) or 0.3 m (relative).

In terms of deployment and operation scenarios for in-coverage, partial-coverage and out-of-coverage NR positioning use cases, TR 38.845 has identified the following: (1) a network coverage: In-network coverage, partial network coverage as well as out-of-network coverage. In addition to scenarios with no GNSS and no network coverage; (2) a radio link: Uu interface (UL/DL interface) based solutions, PC5 interface (SL interface) based solutions and their combinations (hybrid solutions). As well as RAT-independent solutions such as GNSS and sensors; (3) positioning calculation entity: Network-based positioning when the positioning estimation is performed by the network and UE-based positioning when the positioning estimation is performed by the UE; (4) a UE Type: For V2X UEs, this can be a UE installed in a vehicle, a road side unit (RSU), or a vulnerable road user (VRU). Some UEs can have distributed antennas, e.g., multiple antenna patterns that can be leveraged for positioning. UEs can have different power supply limitations, for example VRUs or hand held UEs have limited energy supply compared to other UEs; and (5) spectrum: This can include licensed spectrum and unlicensed spectrum for the Uu interface and the PC5 interface; as well as ITS-dedicated spectrum for the PC5 interface.

In the present disclosure, design aspects related to the configuration and allocation of SL PRSs are provided. The term “SL PRSs,” refers to reference signals transmitted by a SL UE on the SL interface (e.g., PC5 interface), that can be used for SL positioning measurements. SL PRSs can also be referred to as SL sounding reference signal for positioning.

An SL is one of the promising features of NR, targeting verticals such the automotive industry, public safety, industrial internet of things (IIoT) and other commercial application. 3GPP Rel-16 is the first NR release to include sidelink through work item “5G V2X with NR sidelink” with emphasis on V2X and public safety where the requirements are met. In Rel-17, the support of SL has been expanded to other types of UEs such a vulnerable road users (VRUs), pedestrian UEs (PUEs) and other types of hand held devices, by supporting mechanisms for power saving for SL resource allocation as well as mechanisms that enhance reliability and reduce latency of SL transmissions.

Another feature that NR supports is positioning, using the NR radio interface for performing positioning measurements to determine or assist in determining the location of a UE. NR positioning was first introduced using the Uu interface in Rel-16, through work item “NR Positioning Support.” Rel-17 further enhanced accuracy and reduced the latency of NR-based positioning through work item “NR Positioning Enhancements.” In Rel-17, a study was conducted in the RAN on “scenarios and requirements of in-coverage, partial coverage, and out-of-coverage positioning use cases” with accuracy requirements in the 10's of cm range, using the PC5 interface as well as the Uu interface for absolute and relative positioning. In Rel-18 a new study item has been approved to study and evaluate performance and feasibility of potential solutions for SL positioning. In this disclosure the configuration and time/frequency domain allocation of SL PRS is considered.

In the present disclosure, a structure for the SL positioning signal to be used for SL positioning measurements. Structure of the SL PRS includes structure in the time and frequency domains including resource allocation. In addition, the selection of resources for transmission of SL PRSs is also considered. Furthermore, configuration and signaling of SL PRSs is considered.

The present disclosure relates to a 5G/NR communication system. The present disclosure introduces a structure for SL PRSs including the following aspects: (1) configuration of SL PRSs; (2) determination/selection of resource for SL PRSs' and/or (3) allocation of SL PRSs. TABLE 4 shows the resource pools.

TABLE 4 Resources - Logical slots within a resource pool.  ∘ A logical slot index for a slot within a resource pool is denoted as t′_(i) ^(SL).  ∘ A time period expressed in logical slots within a resource pool is denoted as T′. - Logical slots that can be in a resource pool. These are the SL slots before the application of the resource pool bitmap, as described in 3GPP standard specification TS 38.214.  ∘ A logical slot index for a slot that can be in a resource pool is denoted as t_(i) ^(SL).  ∘ A time period expressed in logical slots that can be in a resource pool is denoted as T′. While this is the same notation as used for logical slots within a resource pool the value is different and it may be apparent from the context which value to use. - Physical slots or physical time.  ∘ A Physical slot number (or index) is denoted as n or n′. n is the physical slot number of any physical slot, while n′ is the physical slot number of a slot in the resource pool.  ∘ A time period is expressed as physical time (e.g., in milliseconds (ms)) or in units of physical slots.

When used in the same equation, time units may be the same, i.e.; (1) if logical slots within a resource pool are used in an equation, inequality or expression, the time period in the same equation, inequality or expression may be expressed in units of logical slots within a resource pool; (2) if logical slots that can be in a resource pool are used in an equation, inequality or expression, the time period in the same equation, inequality or expression may be expressed in units of logical slots that can be in a resource pool; and/or (3) if physical slots are used in an equation, inequality or expression, the time period in the same equation, inequality or expression may be expressed in units of physical slots or physical time scaled by the slot duration.

Time units can be converted from one unit to another. For example, for each logical slot index for a slot within a resource pool there is a corresponding physical slot number. The converse is not true, i.e., not every physical slot corresponds to a logical slot within a resource pool.

When converting from physical slot number to logical slot index: (1) if the physical slot is in the resource pool, the corresponding logical slot index within the resource pool is determined; and (2) if the physical slot is not in the resource pool, the index of an adjacent logical slot within the resource pool is determined, wherein one of: (i) the adjacent logical slot is the next logical slot after the physical slot or (ii) the adjacent logical slot is the pervious logical slot before the physical slot.

To convert from physical time (in ms) to time in units of logical slots within a resource pool, the following equation can be used, wherein T is in units of ms and T′ is in units of logical slots within a resource pool:

${T^{\prime} = \left\lceil {\frac{{{T}^{\prime}}_{\max}}{10240{ms}} \times T} \right\rceil},$

wherein, T′_(max) is the number of logical slots within the resource pool in 1024 frames or 10240 ms.

The slot index or the time period provided by higher layers or specified in the specifications can be given in one unit, e.g., in physical slots or in ms, and is converted to a logical slot index or units of logical slots within a resource pool before being used in the corresponding equations, or vice versa.

In the present disclosure a SL PRS refers generically to a physical reference signal transmitted on the SL interface to assist in determining a position of a SL UE based on measurements performed on the SL PRS. In one example, a SL PRS can have a physical signal structure and/or resource allocation similar to the physical signal structure and/or resource allocation of a DL PRS used in DL of the Uu interface in NR, except that it is transmitted/received on the SL interface (PC5 interface).

In another example, a SL PRS can have a physical signal structure and/or resource allocation similar to the physical signal structure and/or resource allocation of a UL positioning sounding reference signal (SRS) used in UL of the Uu interface in NR, except that it is transmitted/received on the SL interface (PC5 interface). In another example, a SL PRS can have a physical signal structure and/or resource allocation combining aspects of the physical signal structure and/or resource allocation of (1) DL PRS used in DL of the Uu interface in NR and (2) UL positioning sounding reference signal (SRS) used in UL of the Uu interface in NR, except that it is transmitted/received on the SL interface (PC5 interface). In another example, a SL PRS can have a new physical signal structure and/or resource allocation for use on the SL interface (PC5 interface).

In one embodiment, the network (e.g., gNB and/or LMF) can configure SL resources for SL PRS and/or SL resources for reporting SL measurements. The network can further configure SL UEs to transmit and/or receive SL PRSs. The network can further configure SL UEs to perform SL positioning measurements.

FIG. 7 illustrates an example of a UE in a network coverage 700 according to embodiments of the present disclosure. An embodiment of the UE in a network coverage 700 shown in FIG. 7 is for illustration only.

A UE is in coverage of a network as shown in FIG. 7 . The network can configure the UE with resources to use for: (1) SL PRSs on the SL interface (PC5 interface); and/or (2) reporting of SL positioning measurements on the SL interface (PC5 interface).

In another embodiment, a SL UE is (pre-)configured SL resources for SL PRS and/or SL resources for reporting SL measurements. The UE can be further configured to transmit and/or receive SL PRSs. The UE can be further configured to perform SL positioning measurements.

The UE can be configured with resources to use for: (1) SL PRSs on the SL interface (PC5 interface); and/or (2) reporting of SL positioning measurements on the SL interface (PC5 interface).

SL PRSs are reference signals transmitted on the SL interface by a first UE. The SL PRSs are received by one or more second UE(s) (e.g., the SL PRS can be unicast or groupcast or broadcast from a first UE to one or more second UEs), wherein the second UE(s) performs SL positioning measurements on the SL PRSs. SL positioning measurements are measurements that aid in finding the position of a SL UE, e.g., the absolute position of the first SL UE and/or the absolute position of the second SL UE, and/or the relative of position of the first SL UE to the second SL UE and/or the relative position of the second SL UE to the first SL UE. Absolute position can be defined in a frame of reference, e.g., the global frame of reference (e.g., using latitude and longitude and/or elevation).

SL positioning measurements can include: (1) SL reference signal time difference (RSTD). For example, the time difference between a PRS received by a SL UE and a reference time; (2) SL reference signal received power (RSRP) of a SL PRS or SL reference signal received path power (RSRPP) of a SL PRS; (3) SL angle of arrival (AoA) of a SL PRS; and (4) SL Rx-Tx time difference. For example, this can be the difference between the receive time of a first SL PRS and the transmit time of a second SL PRS.

FIG. 8 illustrates a flowchart of a method 800 for SL PRSs on a SL interface according to embodiments of the present disclosure. For example, the method 800 as may be performed by a UE such as 111-116 as illustrated in FIG. 1 . An embodiment of the method 800 shown in FIG. 8 is for illustration only. One or more of the components illustrated in FIG. 8 can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions.

In one example, a UE transmits SL PRSs on a SL interface (e.g., PC5 interface). This is illustrated in FIG. 8 .

As illustrated in FIG. 8 , in block 801: The UE is configured for SL positioning. This can include one or more of the following:

-   -   The UE is (pre-)configured for SL positioning;     -   The UE is (pre-)configured for the transmission of SL PRS;     -   The UE is configured by higher layers in the UE for SL         positioning;     -   The UE is configured by higher layers in the UE for the         transmission of SL PRSs;     -   The UE is triggered by higher layers in the UE for SL         positioning;     -   The UE is triggered by higher layers in the UE for transmission         of SL PRSs;     -   The UE is configured by higher layers of another UE for SL         positioning;     -   The UE is configured by higher layers of another UE for the         transmission of SL PRSs;     -   The UE is triggered by higher layers of another UE for SL         positioning;     -   The UE is triggered by higher layers of another UE for         transmission of SL PRSs;     -   The UE is configured by higher layers in the network for SL         positioning;     -   The UE is configured by higher layers in the network for the         transmission of SL PRSs;     -   The UE is triggered by higher layers in the network for SL         positioning; and/or     -   The UE is triggered by higher layers in the network for         transmission of SL PRSs.

In the above examples, the “another UE” can be for example, a group leader, a platoon leader, a UE receiving the SL PRS, a UE performing SL positioning measurements, a UE aggregating SL positioning measurements from one or more other UEs and/or a UE co-coordinating SL positioning.

A sidelink PRS can be transmitted in a SL resource pool (e.g., Tx resource pool).

In one example, the resource pool is configured for SL positioning (e.g., transmission of SL PRS). The resource pool can be used for other SL traffic (e.g., SL communication).

In another example, the resource pool is configured for SL positioning (e.g., transmission of SL PRS). The resource pool is dedicated to SL positioning, e.g., the resource pool is used for SL PRS and SL positioning measurements and/or associated signaling, if any (e.g., associated HARQ feedback and/or associated inter-UE co-ordination signaling, and/or SL positioning configuration messages (e.g., control information associated with SL PRS configuring SL PRS), if any).

In another example, the resource pool is configured for SL positioning (e.g., transmission of SL PRS). The resource pool is dedicated to SL PRSs, e.g., the resource pool is used for SL PRS and/or associated signaling, if any (e.g., associated HARQ feedback and/or associated inter-UE co-ordination signaling, and/or SL PRS configuration messages (e.g., control information associated with SL PRS configuring SL PRS), if any).

In block 802, the UE determines or selects resources for transmission of SL PRS. The resources for SL PRS includes time domain resources, frequency domain resources and/or code domain (e.g., sequence) resources.

In one example, time domain resources can include one or more of: (1) slots for transmission of SL PRS. (2) symbols for transmission of SL PRS. (3) periodicity in time domain for transmission of SL PRS. (4) number of periods for transmission of SL PRS. (5) number of repetitions for transmission of SL PRS within one period.

In one example, frequency domain resources can include one or more of: (1) starting sub-channel for transmission of SL PRSs; (2) ending sub-channel for transmission of SL PRS; (3) number of sub-channels for SL PRS; (4) starting PRB for transmission of SL PRSs; (5) ending PRB for transmission of SL PRS; (6) number of PRBs for SL PRS; (7) starting sub-carrier for transmission of SL PRSs; (8) ending sub-carrier for transmission of SL PRS; (9) number of sub-carriers for SL PRS; (10) transmission comb for SL PRS (e.g., a transmission comb of 2, every other sub-carrier is used for PRS, a transmission comb of 4, every 4th sub-carrier is used for PRS, etc.); and (11) transmission comb offset. The starting sub-channel or starting PRB or start sub-carrier or ending sub-channel or ending PRB or ending sub-carrier can be a sub-channel number or a PRB number or a sub-carrier number, respectively, within a SL BWP or a SL resource pool used for the transmission of the SL PRS.

In one example, code-domain resources can include one or more of: (1) sequence to use for SL PRS. (2) the enablement or not of group hopping and/or sequence hopping.

In one example, the resources used for SL PRS are based on higher layer configuration (e.g., pre-configuration and/or configuration by higher layers of the network and/or configuration of higher layers of another UE and/or configuration by higher layers of the UE).

In one example, resource used for SL PRS are based on sensing. The UE performs sensing within a sensing window. The UE determines a resource for SL PRS based on sensing. For example, the UE determines a resource selection window. The UE determines a subset of candidate resources (e.g., based on sensing) within the resource selection window that can be used for SL PRS. The UE selects a resource within the candidate resource set for SL PRS.

In one example, sensing can be based on full sensing.

In another example, sensing can be based on partial sensing (e.g., periodic-based partial sensing (PBPS) and/or contiguous partial sensing (CPS)).

In another example, there is no sensing, e.g., the UE selects a resource for SL PRS based on random resource selection.

In one example, the UE before transmitting SL PRS on a SL resource, the UE performs re-evaluation check or pre-emption check for the SL resource to be used for the SL PRS.

In block 803, the UE transmits the SL PRS on the determined SL resource.

FIG. 9 illustrates another flowchart of a method 900 for SL PRSs on a SL interface according to embodiments of the present disclosure. For example, the method 900 as may be performed by a UE such as 111-116 as illustrated in FIG. 1 . An embodiment of the method 900 shown in FIG. 9 is for illustration only. One or more of the components illustrated in FIG. 9 can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions.

In one example, a UE receives and measures SL PRSs on a SL interface (e.g., PC5 interface). This is illustrated in FIG. 9 .

In block 901, the UE is configured for SL positioning. This can include one or more of the following:

-   -   The UE is (pre-)configured for SL positioning;     -   The UE is (pre-)configured for the reception/monitoring of SL         PRS;     -   The UE is configured by higher layers in the UE for SL         positioning;     -   The UE is configured by higher layers in the UE for the         reception/monitoring of SL PRSs;     -   The UE is triggered by higher layers in the UE for SL         positioning;     -   The UE is triggered by higher layers in the UE for         reception/monitoring of SL PRSs;     -   The UE is configured by higher layers of another UE for SL         positioning;     -   The UE is configured by higher layers of another UE for the         reception/monitoring of SL PRSs;     -   The UE is triggered by higher layers of another UE for SL         positioning;     -   The UE is triggered by higher layers of another UE for         reception/monitoring of SL PRSs;     -   The UE is configured by higher layers in the network for SL         positioning;     -   The UE is configured by higher layers in the network for the         reception/monitoring of SL PRSs;     -   The UE is triggered by higher layers in the network for SL         positioning; and/or     -   The UE is triggered by higher layers in the network for         reception/monitoring of SL PRSs.

In the above examples, the “another UE” can be for example, a group leader, a platoon leader, a UE transmitting the SL PRS, a UE aggregating SL positioning measurements, a UE aggregating SL positioning measurements from one or more other UEs and/or a UE co-coordinating SL positioning.

A sidelink PRS can be received in a SL resource pool (e.g., Rx resource pool).

In one example, the resource pool is configured for SL positioning (e.g., for having SL PRS). The resource pool can be used for other SL traffic (e.g., SL communication).

In another example, the resource pool is configured for SL positioning (e.g., for having SL PRS). The resource pool is dedicated to SL positioning, e.g., the resource pool is used for SL PRS and SL positioning measurements and/or associated signaling, if any (e.g., associated HARQ feedback and/or associated inter-UE co-ordination signaling, and/or SL positioning configuration messages (e.g., control information associated with SL PRS configuring SL PRS), if any).

In another example, the resource pool is configured for SL positioning (e.g., for having SL PRS). The resource pool is dedicated to SL PRSs, e.g., the resource pool is used for SL PRS and/or associated signaling, if any (e.g., associated HARQ feedback and/or associated inter-UE co-ordination signaling, and/or SL PRS configuration messages (e.g., control information associated with SL PRS configuring SL PRS), if any).

In block 902, the UE determines or monitors resources for reception of SL PRS. The resources for SL PRS includes time domain resources, frequency domain resources and/or code domain (e.g., sequence) resources.

In one example, time domain resources can include one or more of: (1) slots for transmission of SL PRS; (2) symbols for transmission of SL PRS; (3) periodicity in time domain for transmission of SL PRS; (4) number of periods for transmission of SL PRS; and (5) number of repetitions for transmission of SL PRS within one period.

In one example, frequency domain resources can include one or more of: (1) starting sub-channel for transmission of SL PRSs; (2) ending sub-channel for transmission of SL PRS; (3) number of sub-channels for SL PRS; (4) starting PRB for transmission of SL PRSs; (5) ending PRB for transmission of SL PRS; (6) number of PRBs for SL PRS; (7) starting sub-carrier for transmission of SL PRSs; (8) ending sub-carrier for transmission of SL PRS; (9) number of sub-carriers for SL PRS; (10) transmission comb for SL PRS (e.g., a transmission comb of 2, every other sub-carrier is used for PRS, a transmission comb of 4, every 4th sub-carrier is used for PRS, etc.); and (11) transmission comb offset. The starting sub-channel or starting PRB or start sub-carrier or ending sub-channel or ending PRB or ending sub-carrier can be a sub-channel number or a PRB number or a sub-carrier number, respectively, within a SL BWP or a SL resource pool used for the transmission of the SL PRS.

In one example, code-domain resources can include one or more of: (1) sequence to use for SL PRS; and (2) the enablement or not of group hopping and/or sequence hopping.

In one example, the resources used for SL PRS are based on higher layer configuration (e.g., pre-configuration and/or configuration by higher layers of the network and/or configuration of higher layers of another UE and/or configuration by higher layers of the UE). The UE monitors and receives SL PRS in these resources.

In one example, the UE monitors resources for SL PRS (e.g., all or some of the resources of the resources—the UE can be (pre-)configured which resources to monitor). At least based on the monitoring (e.g., by receiving control information associated with SL PRS as described later in this disclosure), the UE can determine whether there is a SL PRS in that resource destined to (intended for) the UE.

In block 903, on the determined SL resource for reception of the SL PRS (e.g., as described in step 902), the UE receives and measures the SL PRS.

Measurements can include, for example: (1) SL reference signal received power (RSRP) of the SL PRS or SL reference signal received path power (RSRPP) of the SL PRS; (2) SL reference signal time difference (RSTD) of the SL PRS relative to a reference time (e.g., the reception time of a second SL PRS); (3) SL angle of arrival measurements of the SL PRS; (4) Tx-Rx time difference measurements; and (5) carrier phase measurements.

In block 904, the UE reports the SL measurements. For example: the reporting can be to (1) higher layers of the UE; (2) the UE(s) transmitting the SL PRS; (3) another UE, e.g., group leader, platoon leader, UE aggregating SL measurements, and/or UE coordinating SL measurements; and (4) the network (e.g., gNB and/or LMF).

FIG. 10 illustrates an example of SL PRS in a slot 1000 according to embodiments of the present disclosure. An embodiment of the SL PRS in a slot 1000 shown in FIG. 10 is for illustration only.

The time domain structure can include one or more time domain structure within a slot. This can include (FIG. 10 ) one or more of: (1) starting symbol of SL PRS; (2) ending symbol of SL PRS; (3) length of SL PRS; and/or (4) the number of consecutive symbols following or preceding the starting or ending symbol, respectively.

FIG. 10 illustrates an example of a SL PRS in a slot. The starting symbol of the SL PRS is symbol 3. The length of the SL PRS in time domain is 4 symbols. The starting sub-channel of the SL PRS is sub-channel 1. The length of the SL PRS in frequency domain is 4 sub-channels.

In one example an AGC symbol is placed before the first symbol of the SL PRS, wherein the AGC symbol is a repetition of the first symbol.

In one example there is no AGC symbol before the first symbol of the PRS.

In one example before the first symbol of the PRS is a SL transmission including configuration information for the SL reference signal. For example, this can be: (1) first stage SCI (e.g., SCI format 1-A or another first stage SCI format); (2) second stage SCI (e.g., SCI format 2-A or 2-B or 2-C or another second stage SCI format), and/or (3) SL shared channel with SL positioning configuration information.

In one example a guard symbol is placed after the last symbol of SL PRS, wherein a guard symbol includes no SL transmission.

In one example there is no guard symbol placed after the last symbol of SL PRS, wherein a guard symbol includes no SL transmission.

FIG. 11 illustrates an example of SL PRS transmission with an AGC symbol and a guard symbol 1100 according to embodiments of the present disclosure. An embodiment of the SL PRS transmission with an AGC symbol and a guard symbol 1100 shown in FIG. 11 is for illustration only.

FIG. 11 is example of SL PRS transmission with an AGC symbol and a guard symbol.

FIG. 12 illustrates an example of SL PRS transmission with configuration information and a guard symbol 1200 according to embodiments of the present disclosure. An embodiment of the SL PRS transmission with configuration information and a guard symbol 1200 shown in FIG. 12 is for illustration only.

FIG. 12 is example of SL PRS transmission with configuration information and a guard symbol.

In one example, the UE is (pre-)configured the first symbol of the SL positioning reference.

In one example, the UE determines the first symbol of SL PRS to be the first symbol after configuration information.

In one example, the UE determines the first symbol of SL PRS to be the first SL symbol of a SL slot.

In one example, the UE determines the first symbol of SL PRS to be the second SL symbol of a SL slot (e.g., the first symbol of the SL slot is an AGC symbol of SL PRS).

In one example, the UE is (pre-)configured the length of the SL positioning reference.

In one example, the length of the SL PRS is the length of the SL slot in SL symbols. None, one or more of the following can be excluded (subtracted from the SL symbols of a slot) from the length of the position reference signal: (1) AGC symbol(s); (2) symbols used for configuration of SL positioning (e.g., for configuration of SL PRS); (3) guard symbol(s); and/or (4) symbol(s) used for PSFCH.

FIG. 13 illustrates an example of time domain structure across slots 1300 according to embodiments of the present disclosure. An embodiment of the time domain structure across slots 1300 shown in FIG. 13 is for illustration only.

Time domain structure across slots. This can include (FIG. 13 ) one or more of example as shown below.

In one example of periodicity and slot offset, as illustrated in FIG. 13 , the period is T_(period) and the offset from a reference slot is T_(offset). In one example, T_(period) is units in slots (or subframes) and T_(offset) is in units of slots (or sub-frames), wherein T_(offset) ∈{0,1, . . . , T_(period)−1}. In one example T_(period) is in units of physical slots or physical time (e.g., milli-seconds). In one example, T_(period) is in units of logical slots that can be in a resource pool. In one example, T_(period) is in units of logical slots in a resource pool. In one example, the reference slot (or reference sub-frame) can be slot 0 of SFN 0 (system frame number 0) or slot 0 of DFN 0 (direct frame number 0).

In one example of repetition factor, as illustrated in FIG. 13 , the repetition faction is N_(rep). This represents the number of repetition of SL PRS in one period. In one example, N_(rep)=1, i.e., there is no repetition, just one transmission of the SL PRS per period.

In one example of repetition gap, as illustrated in FIG. 13 , the repetition gap is T_(gap). This represents the time between two consecutive repetitions of SL PRS in one period. If N_(rep)=1, this parameter may not be needed or used or configured or indicated. In one example T_(gap) is in units of physical slots or physical time (e.g., milli-seconds). In one example, T_(gap) is in units of logical slots that can be in a resource pool. In one example, T_(gap) is in units of logical slots in a resource pool.

In one example, the allocation in the frequency domain can be determined by one or more of: (1) starting frequency in the frequency domain. The starting frequency in the frequency domain can be one of: (i) a starting sub-channel; (ii) a starting PRB; and/or (iii) a starting sub-carrier; (2) ending frequency in the frequency domain. The ending frequency in the frequency domain can be one of: (i) an ending sub-channel; (ii) an ending PRB; and/or (iii) an ending sub-carrier; and/or (3) length in the frequency domain, i.e., the number of consecutive sub-channels following or preceding the starting or ending frequency, respectively. The length in the frequency domain can be one of: (i) a length in sub-channels; (ii) a length in PRBs; and/or (iii) a length in sub-carriers. The starting sub-channel or starting PRB or start sub-carrier or ending sub-channel or ending PRB or ending sub-carrier can be a sub-channel number or a PRB number or a sub-carrier number, respectively, within a SL BWP or a SL resource pool used for the transmission of the SL PRS.

In one example, a transmission comb is used when transmitting the SL PRS. For example, if a transmission comb of N is used, every N^(th) sub-carrier is used for the transmission of the PRS. In another example, if a transmission comb of N is used, every N^(th) PRB is used for the transmission of the PRS. In another example, if a transmission comb of N is used, every N^(th) sub-channel is used for the transmission of the PRS. N can be selected from one or more of these values: 1, 2, 4, 6, 8, or 12.

FIG. 14 illustrates an example of start of the frequency domain allocation for positioning 1400 according to embodiments of the present disclosure. An embodiment of the start of the frequency domain allocation for positioning 1400 shown in FIG. 14 is for illustration only.

In one example, if a transmission comb of N is used, a transmission comb offset is used, wherein the transmission comb offset can be between 0, . . . ,N−1. The transmission comb offset determines the first transmission instance relative to the start of the frequency domain allocation of the SL PRS.

For example, in FIG. 14 , the start of the frequency domain allocation for positioning is sub-channel 0. The sub-channel size is 10 PRBs. The size of the frequency domain allocation is 4 sub-channels. The transmission comb is N=4, i.e., every 4th sub-carrier is used for PRS. The transmission comb offset is 2.

In one example, the transmission comb offset is for the first symbol (i.e., symbol index 0) of the PRS. Additional offset is added for the other symbols. In one example, the additional offset for each symbol depends on symbol index (e.g., relative to the first symbol) of the SL PRS as illustrated in TABLE 5.

First instance of SL PRS in frequency domain=(Reference instance in frequency domain+transmission comb offset+n′) mod Transmission Comb.

An instance can be one of (1) a sub-carrier, (2) a PRB, or (3) a sub-channel.

A reference instance in frequency domain can be the first instance allocated in frequency in frequency domain, e.g., an instance with the lowest frequency allocation in the allocated resources in frequency domain.

n′ is an offset that depends on the symbols index. In one example, the symbol index is relative to the first SL PRS symbol, i.e., first SL PRS symbol has index 0, next SL PRS symbol has index 1, and so on. In one example, the symbol index is relative to the first symbol of the slot. In one example, the symbol index is relative to the first SL symbol of the slot.

mod is the modulo operator, where x mod N equals the remainder from the division of x by N.

TABLE 5 Symbol index dependent additional offset (n′) Tx Symbol index of SL PRS Comb 0 1 2 3 4 5 6 7 8 9 10 11 12 13 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 1 0 1 0 1 0 1 0 1 0 1 0 1 3 0 1 2 0 1 2 0 1 2 0 1 2 0 1 4 0 2 1 3 0 2 1 3 0 2 1 3 0 2 6 0 3 1 4 2 5 0 3 1 4 2 5 0 3 8 0 4 2 6 1 5 3 7 0 4 2 6 1 5 12 0 6 3 9 1 7 4 10 2 8 5 11 0 6

In one example, not all columns of TABLE 5 are needed. For example, if the maximum sidelink PRS symbol length is 12, the last two columns of TABLE 5 are not needed.

FIG. 15 illustrates an example of transmitted sub-carriers for SL PRS 1500 according to embodiments of the present disclosure. An embodiment of the transmitted sub-carriers for SL PRS 1500 shown in FIG. 15 is for illustration only.

FIG. 15 is an example showing the transmitted sub-carriers for SL PRS in each symbol for PRB 0. The transmission comb is N=4. The transmission comb offset is 2 as shown below.

-   -   In symbol with index 0 the transmission comb offset is (2+0) mod         4=2;     -   In symbol with index 1 the transmission comb offset is (2+2) mod         4=0;     -   In symbol with index 2 the transmission comb offset is (2+1) mod         4=3; and     -   In symbol with index 3 the transmission comb offset is (2+3) mod         4=1.

SL is one of the promising features of NR, targeting verticals such the automotive industry, public safety, industrial internet of things (IIoT) and other commercial application. SL has been first introduced to NR in release 16, with emphasis on V2X and public safety where the requirements are met. The support of SL has been expanded to other types of UEs such a vulnerable road users (VRUs), pedestrian UEs (PUEs) and other types of hand held devices, by supporting mechanisms for power saving for SL resource allocation as well as mechanisms that enhance reliability and reduce latency of SL transmissions.

Another feature that NR supports is positioning, using the NR radio interface for performing positioning measurements to determine or assist in determining the location of a UE. NR positioning was first introduced using the Uu interface in Rel-16, and further enhanced for improved accuracy and reduced latency in Rel-17. In Rel-18 a new study item has been approved to study and evaluate performance and feasibility of potential solutions for SL positioning. In this disclosure the configuration and time/frequency domain allocation of SL PRS is considered.

In the present disclosure, a signaling content for the SL positioning signal to be used for SL positioning measurements is considered. A transmission of SL PRS includes reference signal used for position and associated control information. Control information can include a first stage (or first part) control information and a second stage (or second part) control information.

In the following examples, time can be expressed in one of following: (1) logical slots within a resource pool; (i) a logical slot index for a slot within a resource pool is denoted as t′_(i) ^(SL) and/or a time period expressed in logical slots within a resource pool is denoted as T′; (2) logical slots that can be in a resource pool. These are the SL slots before the application of the resource pool bitmap, as described in TS 38.214: (i) a logical slot index for a slot that can be in a resource pool is denoted as t_(i) ^(SL) and/or (ii) a time period expressed in logical slots that can be in a resource pool is denoted as T′. While this is the same notation as used for logical slots within a resource pool the value is different and it may be apparent from the context which value to use; and (3) physical slots or physical time: (i) a physical slot number (or index) is denoted as n or n′. n is the physical slot number of any physical slot, while n′ is the physical slot number of a slot in the resource pool and/or (ii) a time period is expressed as physical time (e.g., in milliseconds (ms)) or in units of physical slots.

When used in the same equation, time units may be the same, i.e.: (1) if logical slots within a resource pool are used in an equation, inequality or expression, the time period in the same equation, inequality or expression may be expressed in units of logical slots within a resource pool; (2) if logical slots that can be in a resource pool are used in an equation, inequality or expression, the time period in the same equation, inequality or expression may be expressed in units of logical slots that can be in a resource pool; and (3) if physical slots are used in an equation, inequality or expression, the time period in the same equation, inequality or expression may be expressed in units of physical slots or physical time scaled by the slot duration.

Time units can be converted from one unit to another.

For example, for each logical slot index for a slot within a resource pool there is a corresponding physical slot number. The converse is not true, i.e., not every physical slot corresponds to a logical slot within a resource pool. When converting from physical slot number to logical slot index: (1) if the physical slot is in the resource pool, the corresponding logical slot index within the resource pool is determined and (2) if the physical slot is not in the resource pool, the index of an adjacent logical slot within the resource pool is determined, wherein one of: (i) the adjacent logical slot is the next logical slot after the physical slot and/or (ii) the adjacent logical slot is the pervious logical slot before the physical slot.

To convert from physical time (in ms) to time in units of logical slots within a resource pool, the following equation can be used, wherein T is in units of ms and T′ is in units of logical slots within a resource pool:

$T^{\prime} = \left\lceil {\frac{{{T}^{\prime}}_{\max}}{10240{ms}} \times T} \right\rceil$

wherein, T′max is the number of logical slots within the resource pool in 1024 frames or 10240 ms.

The slot index or the time period provided by higher layers or specified in the specifications can be given in one unit, e.g., in physical slots or in ms, and is converted to a logical slot index or units of logical slots within a resource pool before being used in the corresponding equations, or vice versa.

In the present disclosure, a SL PRS refers generically to a physical reference signal transmitted on the SL interface to assist in determining a position of a SL UE based on measurements performed on the SL PRS. In one example, a SL PRS can have a physical signal structure and/or resource allocation similar to the physical signal structure and/or resource allocation of a DL PRS used in DL of the Uu interface in NR, except that it is transmitted/received on the SL interface (PC5 interface).

In another example, a SL PRS can have a physical signal structure and/or resource allocation similar to the physical signal structure and/or resource allocation of a UL positioning sounding reference signal (SRS) used in UL of the Uu interface in NR, except that it is transmitted/received on the SL interface (PC5 interface).

In another example, a SL PRS can have a physical signal structure and/or resource allocation combining aspects of the physical signal structure and/or resource allocation of (1) DL PRS used in DL of the Uu interface in NR and (2) UL positioning sounding reference signal (SRS) used in UL of the Uu interface in NR, except that it is transmitted/received on the SL interface (PC5 interface). In another example, a SL PRS can have a new physical signal structure and/or resource allocation for use on the SL interface (PC5 interface).

A reference signal used for positioning can be pre-configured and/or configured and/or allocated a network and/or by a SL UE.

In one embodiment, the network (e.g., gNB and/or LMF) can configure SL resources for SL PRS and/or SL resources for reporting SL measurements. The network can further configure SL UEs to transmit and/or receive SL PRSs. The network can further configure SL UEs to perform SL positioning measurements.

A UE is in coverage of a network as shown in FIG. 7 . The network can configure the UE with resources to use for: (1) SL PRSs on the SL interface (PC5 interface) and (2) reporting of SL positioning measurements on the SL interface (PC5 interface).

In another embodiment, a SL UE is (pre-)configured SL resources for SL PRS and/or SL resources for reporting SL measurements. The UE can be further configured to transmit and/or receive SL PRSs. The UE can be further configured to perform SL positioning measurements.

The UE can be configured with resources to use for: (1) SL PRSs on the SL interface (PC5 interface) and (2) reporting of SL positioning measurements on the SL interface (PC5 interface).

SL PRSs are reference signals transmitted on the SL interface by a first UE. The SL PRSs are received by one or more second UE(s) (e.g., the SL PRS can be unicast or groupcast or broadcast from a first UE to one or more second UEs), wherein the second UE(s) performs SL positioning measurements on the SL PRSs. SL Positioning measurements are measurements that aid in finding the position of a SL UE, e.g., the absolute position of the first SL UE and/or the absolute position of the second SL UE, and/or the relative of position of the first SL UE to the second SL UE and/or the relative position of the second SL UE to the first SL UE. Absolute position can be defined in a frame of reference, e.g., the Global frame of reference (e.g., using latitude and longitude and/or elevation).

SL positioning measurements can include:

-   -   SL reference signal time difference (RSTD). For example, the         time difference between a PRS received by a SL UE and a         reference time;     -   SL reference signal received power (RSRP) of a SL PRS;     -   SL reference signal received path power (RSRPP) or a SL PRS;     -   SL Angle of Arrival (AoA) of a SL PRS; and     -   SL Rx-Tx time difference. For example, this can be the         difference between the receive time of a first SL PRS and the         transmit time of a second SL PRS.

A sidelink positioning reference signal can be transmitted in a SL resource pool (e.g., Tx resource pool).

In one example, the resource pool is configured for SL positioning (e.g., transmission of SL positioning reference signal). The resource pool can be used for other SL traffic (e.g., SL communication).

In another example, the resource pool is configured for SL positioning (e.g., transmission of SL positioning reference signal). The resource pool is dedicated to SL positioning, e.g., the resource pool is used for SL positioning reference signal and SL positioning measurements and/or associated signaling, if any (e.g., associated HARQ feedback and/or associated inter-UE co-ordination signaling, and/or SL positioning configuration messages (e.g., control information associated with SL PRS configuring SL PRS), if any).

In one instance, if the UE measuring the SL PRS does not receive SL PRS (e.g., SL PRS RSRP is below a threshold), the UE receiving the SL PRS sends a NACK to the UE transmitting the SL PRS to re-transmit the SL-PRS.

In one instance, the UE measuring the SL PRS can send an inter-UE co-ordination request to the UE transmitting the SL PRS to indicated preferred and/or non-preferred resources for the transmissions of the SL PRS.

In another example, the resource pool is configured for SL positioning (e.g., transmission of SL positioning reference signal). The resource pool is dedicated to SL positioning reference signals, e.g., the resource pool is used for SL positioning reference signal and/or associated signaling, if any (e.g., associated HARQ feedback and/or associated inter-UE co-ordination signaling, and/or SL positioning reference signal configuration messages (e.g., control information associated with SL PRS configuring SL PRS), if any).

In one instance, if the UE measuring the SL PRS does not receive SL PRS (e.g., SL PRS RSRP is below a threshold), the UE receiving the SL PRS sends a NACK to the UE transmitting the SL PRS to re-transmit the SL-PRS.

In one instance, the UE measuring the SL PRS can send an inter-UE co-ordination request to the UE transmitting the SL PRS to indicated preferred and/or non-preferred resources for the transmissions of the SL PRS.

In one embodiment the content of control information (signaling) associated with a reference signal for SL positioning measurements (e.g., a SL PRS) is considered.

In the following examples, the SL control information associated with SL-PRS is denoted as SCI-P. The reference signal for SL positioning measurement (or SL PRS) is denoted as SL-PRS. Furthermore, if SL control information associated with SL-PRS includes a first stage (or first part) SL control information and a second stage (or second part) SL control information. The first stage SL control information is denoted as SCI1-P. The second stage SL control information is denoted as SCI2-P

In one example, the control information associated with the reference signal for SL positioning measurements is transmitted in a same slot as the slot of the reference signal for SL positioning measurements.

In one example, the control information associated with SL-PRS includes: (1) a first stage (or first part) SL control information (e.g., SCI1-P). (2) a second stage (or second part) SL control information (e.g., SCI2-P). This is illustrated in FIG. 16 .

FIG. 16 illustrates an example of control information associated with the reference signal for SL positioning measurements 1600 according to embodiments of the present disclosure. An embodiment of the control information associated with the reference signal for SL positioning measurements 1600 shown in FIG. 16 is for illustration only.

In one example, the first stage (or first part) SL control information (e.g., SCI1-P) is transmitted in or multiplexed in a PSCCH.

SCI1-P includes one or more of the fields (for example it may include all the fields) illustrated in TABLE 6. In one example, SCI1-P is a SCI format 1-A, with fields as described in TABLE 6 being applied to SL-PRS.

TABLE 6 Fields of SCI1-P Field Size and Description Priority Size: 3 bits This parameter determines the priority of SL transmission which includes the reference signal for SL positioning measurements. Value “000” of priority field corresponds to priority value “1,” value “001” of priority field corresponds to priority value “2,” and so on Frequency Resource Size is $\left\lceil {\log_{2}\frac{N_{subChannet}^{SL}\left( {N_{subChannel}^{SL} + 1} \right)}{2}} \right\rceil$ bits if two resource allocations Assignment (including that of the current slot) for SL-PRS are signaled. Size is $\log_{2}\frac{{N_{subChannet}^{SL}\left( {N_{subChannel}^{SL} + 1} \right)}\left( {{2N_{subChannel}^{SL}} + 1} \right)}{6}$ bits if three resource allocations (including that of the current slot) for SL-PRS are signaled. This parameter determines the frequency resources allocated to SL-PRS. Time resource Size is 5 bits if two resource allocations (including that of the current slot) for assignment SL-PRS are signaled. Size is 9 bits if three resource allocations (including that of the current slot) for SL-PRS are signaled. Resource Size: ┌log₂ N_(rsv)_period┐ bits, wherein N_(rsv)_period is the number of entries in the reservation higher layer parameter sl-resourceReservationPeriodList, if higher layer period parameter sl-MultiReserveResource is configured. Size is 0 bits if higher layer parameter sl-MultiReserveResource is not configured. This parameter can signal the periodicity of SL-PRS. DMRS pattern Size ┌log₂ N_(pattern)┐ bits, wherein N_(pattern) is the number of DMRS patterns configured by higher layer parameter sl-PSSCH-DMRS-TimePatternList. In one example, this field is reserved for SCI1-P. 2^(nd) stage SCI Size 2 bits. Format Beta_offset Size 2 bits. indicator In one example, this field is reserved for SCI1-P. Number of Size 1 bit DMRS port In one example, this field is reserved for SCI1-P. Modulation Size 5 bits and coding In one example, this field is reserved for SCI1-P. scheme Additional Size 0, 1, or 2 bits MCS table In one example, this field, if present, is reserved for SCI1-P. indicator PSFCH Size 0 or 1 bit overhead In one example, this field, if present, is reserved for SCI1-P. indication Reserved a number of bits as determined by higher layer parameter sl-NumReservedBits.

In one example, the first stage (or first part) SL control information is SCI Format 1-A, as described in TABLE 6, can be further described by the following examples.

In one example, the priority field can be one or more of:

-   -   Specified in the system specification. In one example, the value         specified in the system specification is used if no other value         is (pre-)configured;     -   Pre-configured;     -   Configured/updated by higher layer configuration (e.g., through         Uu RRC interface by the network, or through PC5 RRC interface of         another UE);     -   Configured/updated by MAC CE signaling (e.g., through Uu MAC CE         interface by the network, or through PC5 MAC CE interface of         another UE);     -   Configured/updated L1 control signaling (e.g., through DCI by         the network, or through SCI (first and/or second stage SCI) of         another UE);     -   Determined by the UE's implementation;     -   The (pre-)configuration can be for a resource pool; and/or     -   The (pre-)configuration can be for the UE.

In one example, the size of the frequency allocation N_(subChannel) ^(SL) can be one or more of:

-   -   Specified in the system specification. In one example, the value         specified in the system specification is used if no other value         is (pre-)configured;     -   Pre-configured;     -   Configured/updated by higher layer configuration (e.g., through         Uu RRC interface by the network, or through PC5 RRC interface of         another UE);     -   Configured/updated by MAC CE signaling (e.g., through Uu MAC CE         interface by the network, or through PC5 MAC CE interface of         another UE);     -   Configured/updated L1 control signaling (e.g., through DCI by         the network, or through SCI (first and/or second stage SCI) of         another UE);     -   Determined by sensing in the UE, such that the size of the         frequency allocation N_(subChannel) ^(SL) is no larger than the         available contiguous subchannels in a slot after resource         exclusion as described in 3GPP standard specification TS 38.214;     -   Determined by the UE's implementation;     -   The (pre-)configuration can be for a resource pool; and/or     -   The (pre-)configuration can be for the UE.

In one example, the maximum size of the frequency allocation N_(subChannel-max) ^(SL) and/or the minimum size of the frequency allocation N_(subChannel-min) ^(SL) can be one or more of:

-   -   Specified in the system specification. In one example, the value         specified in the system specification is used if no other value         is (pre-)configured;     -   Pre-configured;     -   Configured/updated by higher layer configuration (e.g., through         Uu RRC interface by the network, or through PC5 RRC interface of         another UE);     -   Configured/updated by MAC CE signaling (e.g., through Uu MAC CE         interface by the network, or through PC5 MAC CE interface of         another UE);     -   Configured/updated L1 control signaling (e.g., through DCI by         the network, or through SCI (first and/or second stage SCI) of         another UE);     -   Determined by the UE's implementation;     -   The (pre-)configuration can be for a resource pool; and/or     -   The (pre-)configuration can be for the UE.

The UE performs sensing and determines the available sub-channels in a slot after resource exclusion as described in 3GPP standard specification TS 38.214. The UE can select N_(subChannel) ^(SL) contiguos sub Channels for SL-PRS, such that N_(subChannel-min) ^(SL)<N_(subChannel) ^(SL)≤N_(subChannel-max) ^(SL). In one example, the UE selects that largest possible number of sub-channels available in a slot after resource exclusion that does not exceed N_(subChannel-max) ^(SL), may at least be N_(subChannel-min) ^(SL) sub-channels.

In one example, any of the periodicities included in sl-resourceReservationPeriodList can be used as periodicity of SL-PRS. In another example, only a subset, X, of the periodicities in sl-resourceReservationPeriodList can be used for SL-PRS. This subset of periodicities, can be:

-   -   Specified in the system specification. In one example, the value         specified in the system specification is used if no other value         is (pre-)configured. In one example         sl-resourceReservationPeriodList, can be used if one other value         is (pre-)configured;     -   Pre-configured;     -   Configured/updated by higher layer configuration (e.g., through         Uu RRC interface by the network, or through PC5 RRC interface of         another UE);     -   Configured/updated by MAC CE signaling (e.g., through Uu MAC CE         interface by the network, or through PC5 MAC CE interface of         another UE);     -   Configured/updated L1 control signaling (e.g., through DCI by         the network, or through SCI (first and/or second stage SCI) of         another UE);     -   Determined by the UE's implementation;     -   The (pre-)configuration can be for a resource pool; and/or     -   The (pre-)configuration can be for the UE.

The number of bits used to signal the periodicity of SL-PRS is n_(per)=┌log₂∥X∥┐, wherein ∥X∥ is the size of subset X. In one example, n_(per) are the most significant bits of ┌log₂ N_(rsv_period)┐ and the least significant bits are reserved (e.g., set to 0). In another example, n_(per) are the least significant bits of ┌log₂ N_(rsv_period)┐ and the most significant bits are reserved (e.g., set to 0). In one example, the size of “Resource reservation period” field is set to ┌log₂∥X∥┐.

In another example, the subset X includes one periodicity, and there is no further signaling of the periodicity in the first stage SL control information. The ┌log₂ N_(rsv_period)┐ are reserved in this case (e.g., set to 0). In one example, if X includes one periodicity, the field “Resource reservation period” is absent.

In one example, the “2^(nd) stage SCI Format” field is set to 11, which indicates that the associated 2^(nd) stage SCI format is a SCI format for a SL positioning related transmission (e.g., SCI2-P). In one example SCI2-P can be designated as SCI format 2-D. When the associated second stage SCI is SCI2-P, the first stage SCI format may be SCI1-P.

In one example, the “2^(nd) stage SCI Format” field is reserved (e.g., bits set to 0). The resource pool is configured such that the number of reserved bits in the first stage SCI (in SL-PSCCH-Config) is greater than 0, e.g., sl-NumReservedBits can be set to 2 or 3 or 4. One of the bits (other than the bit used for conflict capability signaling, if configured) is used to signal that associated SL transmission is SL positioning related transmission. E.g., one of the bits (other than the bit used for conflict capability signaling, if configured) is used to indicate that the first stage SCI format is associated with SL-PRS (e.g., SCI1-P).

In one example, the second stage (or second part) SL control information (e.g., SCI2-P) is transmitted in or multiplexed in a Physical Sidelink Shared Channel (PSSCH).

SCI2-P can include one or more of the following examples.

FIGS. 17A-17H illustrate example of time domain information 1700 according to embodiments of the present disclosure. An embodiment of the time domain information 1700 shown in FIG. 17A-17H is for illustration only.

In one example, information related to time domain behavior of SL-PRS can be included. This can include: (1) the starting symbol of SL-PRS in a slot. In one example, the starting symbol of SL-PRS in a slot is signaled. In one example, the SL-PRS starts in the first symbol after the physical channel conveying SCI2-P, and is not signaled in SCI2-P, as illustrated in FIGS. 17A, 17B, 17C, and 17D. In one example, the SL-PRS starts in the second symbol after the physical channel conveying SCI2-P, and is not signaled in SCI2-P, wherein the first symbol after SCI2-P is a duplicate symbol (e.g., AGC symbol) of the first SL-PRS symbol, as illustrated in FIGS. 17E, 17F, 17G, and 17H. In one example, the SL-PRS starts in the second symbol after the physical channel conveying SCI2-P, and is not signaled in SCI2-P, wherein the first symbol after SCI2-P is a gap symbol (e.g., with no SL transmission). In one example, the SL-PRS starts in the third symbol after the physical channel conveying SCI2-P, and is not signaled in SCI2-P, wherein the first symbol after SCI2-P is a gap symbol (e.g., with no SL transmission), and the second symbol after SCI2-P is a duplicate symbol (e.g., AGC symbol) of the first SL-PRS symbol; (2) the length in symbols of SL-PRS within a slot. In one example, the length of SL-PRS within a slot is signaled. In one example, the length of SL-PRS is not signaled in SCI-P, and one of the following: (i) the length of SL-PRS is such that the last SL-PRS symbol is the last SL symbol a slot, as illustrated in FIGS. 17A and 17E; (ii) the length of SL-PRS is such that the last SL-PRS symbol is the second from last SL symbol a slot, wherein the last SL symbol of slot is a gap symbol (e.g., with no SL transmission), as illustrated in FIGS. 17B and 17F; (iii) if a SL slot includes PSFCH, the length of SL-PRS is such that the last SL-PRS symbol is the SL symbol before the start of PSFCH, as illustrated in FIGS. 17C and 17G and (iv) if a SL slot includes PSFCH, the length of SL-PRS is such that the last SL-PRS symbol is the second SL symbol before the start of PSFCH, wherein the symbol between the end of SL-PRS and start of PSFCH is a gap symbol (e.g., with no SL transmission), as illustrated in FIGS. 17D and 17H; (3) the ending symbol of SL-PRS in a slot; (4) whether or not SL-PRS is one shot, N-shots or periodic; and/or (5) the periodicity of SL-PRS across slots.

In one example, information related to frequency domain behavior of SL-PRS can be included. This can include: (1) the starting sub-channel (or PRB or sub-carrier) of SL-PRS; (2) the number of sub-channels (or PRBs or sub-carriers) of SL-PRS; (3) the ending sub-channel (or PRB or sub-carrier) of SL-PRS; (4) Comb size N, wherein N∈{1, 2, 4, 6, 8, 12}. In one example, N=1, i.e., every sub-carrier can be used for the SL positioning reference signal within the frequency domain allocation for SL PRS; and (5) the Comb offset: in one example, the same transmission comb offset is used in all symbols of a slot. In one example, the transmission combs are fully staggered. In one example, the transmission combs are partially staggered. The starting sub-channel or starting PRB or start sub-carrier or ending sub-channel or ending PRB or ending sub-carrier can be a sub-channel number or a PRB number or a sub-carrier number, respectively, within a SL BWP or a SL resource pool used for the transmission of the SL PRS.

In one example, information related to the sequence generation of SL-PRS can be included (e.g., PRS e.g., hopping type, sequence ID): in one instance, the sequence used for SL-PRS can be based UE's source ID or destination ID (e.g., 12 LSBs or 12 MSBs) or TMSI (Temporary Mobile Subscribed Identity) (e.g., 12 LSBs or 12 MSBs) or IMEI (International Mobile Equipment Identity) (e.g., 12 LSBs or 12 MSBs).

In one example, source and/or destination IDs can be included.

The aforementioned parameters can be included in SCI-P (e.g., SCI1-P and/or SCI2-P) and/or (pre-)configured and/or determined based on system specifications and/or determined based on other fields in SCI format 1-A or a field in the second stage SCI format (e.g., SCI format 2-A, 2-B or 2-C). In one example, if the aforementioned parameters are specified by system specifications and/or (pre-)configured and are then further included in SCI-P (e.g., SCI1-P and/or SCI2-P). The value of the corresponding parameter in SCI-P (e.g., SCI1-P and/or SCI2-P) can override a system specified or (pre-)configured value.

In one example, the first stage SCI is mapped to PSCCH, and the second stage SCI is mapped to a PSSCH-like channel. In one example, PSCCH follows the design as described in 3GPP standard specification TS 38.211, wherein PSCCH can occupy the first 2 or 3 symbols after the AGC symbol (or duplicate symbol). The second stage SCI occupies the remaining PRBs of the PSCCH symbols such the PRBs and/or sub-channels occupied by the first stage SCI and the second stage SCI are the same as the PRBs and/or sub-channels occupied by SL PRS.

In one example, the PSCCH DMRS occupies 3 REs per PRB (e.g., sub-carriers 1, 5 and 9), i.e., the sub-carriers occupied by PSCCH DMRS can be expressed as k=nN_(sc) ^(RB)+4k′+1, wherein, N_(sc) ^(RB)=12, the number of sub-carriers per PRB, and n is the PRB number and k′=0, 1, 2.

In one example, the remaining PRBs of each PSCCH symbol are used for 2′ stage SCI (e.g., PSSCH without SL_SCH). In one example, the sub-carriers occupied by PSSCH DMRS (e.g., for 2^(nd) stage SCI) can be expressed as one of: (1) k=nN_(sc) ^(RB)+4k′+0, wherein, N_(sc) ^(RB)=12, the number of sub-carriers per PRB, and n is the PRB number and k′=0, 1, 2. O can be one of 0 or 1 or 2 or 3. In this example, there are 3 PSSCH DMRS sub-carriers per PRB; (2) k=nN_(sc) ^(RB)+3k′+0, wherein, N_(sc) ^(RB)=12, the number of sub-carriers per PRB, and n is the PRB number and k′=0, 1, 2, 3. O can be one of 0 or 1 or 2. In this example, there are 4 PSSCH DMRS sub-carriers per PRB; (3) k=nN_(sc) ^(RB)+2k′+0, wherein, N_(sc) ^(RB)=12, the number of sub-carriers per PRB, and n is the PRB number and k′=0, 1, 2, 3, 4, 5. O can be one of 0 or 1. In this example, there are 6 PSSCH DMRS sub-carriers per PRB; or (4) k=nN_(sc) ^(RB)+6k′+0, wherein, N_(sc) ^(RB)=12, the number of sub-carriers per PRB, and n is the PRB number and k′=0, 1. O can be one of 0 or 1 or 2 or 3 or 4 or 5. In this example, there are 2 PSSCH DMRS sub-carriers per PRB.

In one example, the number PSCCH symbols is 2 and PSSCH DMRS REs are present in both symbols.

In one example, the number PSCCH symbols is 2 and PSSCH DMRS REs are present in the first symbol only.

In one example, the number PSCCH symbols is 2 and PSSCH DMRS REs are present in the second symbol only.

In one example, the number PSCCH symbols is 3 and PSSCH DMRS REs are present in all symbols.

In one example, the number PSCCH symbols is 3 and PSSCH DMRS REs are present in the first and third symbols only.

In one example, the number PSCCH symbols is 3 and PSSCH DMRS REs are present in the first and second symbols only.

In one example, the number PSCCH symbols is 3 and PSSCH DMRS REs are present in the second and third symbols only.

In one example, the number PSCCH symbols is 3 and PSSCH DMRS REs are present in the first symbol only.

In one example, the number PSCCH symbols is 3 and PSSCH DMRS REs are present in the second symbol only.

In one example, the number PSCCH symbols is 3 and PSSCH DMRS REs are present in the third symbol only.

In one example, the control information associated with SL-PRS is transmitted in a single stage, and is denoted as SCI-P. This is illustrated in FIG. 18 .

FIG. 18 illustrates an example of control information associated with the reference signal for SL positioning measurements 1800 according to embodiments of the present disclosure. An embodiment of the control information associated with the reference signal for SL positioning measurements 1800 shown in FIG. 18 is for illustration only.

The SL control information associated with the PRS (denoted as SCI-P) can be included in PSSCH. Wherein the PSSCH is scheduled by a corresponding PSCCH in the same slot. The PSCCH includes SCI Format 1-A as described in TS 38.212.

In one example, the SCI-P is included in a second stage SCI in PSSCH (e.g., SCI Format 2-D), and there is no addition information multiplexed in PSSCH (i.e., no SL-SCH). SCI Format 2-D can be indicated in the “2nd stage SCI format” field of the first stage SCI format (e.g., SCI format 1-A).

In one example, the SCI-P is included in a second stage SCI in PSSCH (e.g., SCI Format 2-D), and there is a SL-SCH channel that includes a MAC CE that also conveys SCI-P. No additional SL data is multiplexed in the SL-SCH. SCI Format 2-D can be indicated in the “2nd stage SCI format” field of the first stage SCI format (e.g., SCI format 1-A).

In one example, the SCI-P is included in a second stage SCI in PSSCH (e.g., SCI Format 2-D), and there is a SL-SCH channel that includes a MAC CE that also conveys SCI-P, the SL-SCH can also multiplex other SL-data. SCI Format 2-D can be indicated in the “2′ stage SCI format” field of the first stage SCI format (e.g., SCI format 1-A).

In one example, the SCI-P is included in a SL-SCH channel that includes a MAC CE that also conveys SCI-P. No additional SL data is multiplexed in the SL-SCH. In one example, sl-NumReservedBits can be set to 2 or 3 or 4. One or more of the bits (other than the bit used for conflict capability signaling, if configured) is used to indicate that the aperiodic reserved resources and/or the periodic reserved resources (in one example, one of the sl-NumReservedBits can be used for indicating periodic reserved resources, one of the sl-NumReservedBits can be used for indicating aperiodic reserved resources) are used for SL-PRS.

In one example, the SCI-P is included in a SL-SCH channel that includes a MAC CE that also conveys SCI-P, the SL-SCH can also multiplex other SL-data. One or more of the bits (other than the bit used for conflict capability signaling, if configured) is used to indicate that the aperiodic reserved resources and/or the periodic reserved resources (in one example, one of the sl-NumReservedBits can be used for indicating periodic reserved resources, one of the sl-NumReservedBits can be used for indicating aperiodic reserved resources) are used for SL-PRS.

In one example, the SCI-P can include one or more of the following examples.

FIGS. 19A-H illustrate examples of time domain information 1900 according to embodiments of the present disclosure. An embodiment of the time domain information 1900 shown in FIGS. 19A-H is for illustration only.

In one example, information related to time domain behavior of SL-PRS can be included. This can include: (1) the starting symbol of SL-PRS in a slot. In one example, the starting symbol of SL-PRS in a slot is signaled. In one example, the SL-PRS starts in the first symbol after the physical channel conveying SCI-P, and is not signaled in SCI-P, as illustrated in FIGS. 19A, 19B, 19C and 19D. In one example, the SL-PRS starts in the second symbol after the physical channel conveying SCI-P, and is not signaled in SCI-P, wherein the first symbol after SCI-P is a duplicate symbol (e.g., AGC symbol) of the first SL-PRS symbol, as illustrated in FIGS. 19E, 19F, 19G and 19H. In one example, the SL-PRS starts in the second symbol after the physical channel conveying SCI-P, and is not signaled in SCI-P, wherein the first symbol after SCI-P is a gap symbol (e.g., with no SL transmission). In one example, the SL-PRS starts in the third symbol after the physical channel conveying SCI-P, and is not signaled in SCI-P, wherein the first symbol after SCI-P is a gap symbol (e.g., with no SL transmission), and the second symbol after SCI-P is a duplicate symbol (e.g., AGC symbol) of the first SL-PRS symbol; (2) the length in symbols of SL-PRS within a slot. In one example, the length of SL-PRS within a slot is signaled. In one example, the length of SL-PRS is not signaled in SCI-P, and one of the following: (i) the length of SL-PRS is such that the last SL-PRS symbol is the last SL symbol a slot, as illustrated in FIGS. 19A and 19E; the length of SL-PRS is such that the last SL-PRS symbol is the second from last SL symbol a slot, wherein the last SL symbol of slot is a gap symbol (e.g., with no SL transmission), as illustrated in FIGS. 19B and 19F; (ii) if a SL slot includes PSFCH, the length of SL-PRS is such that the last SL-PRS symbol is the SL symbol before the start of PSFCH, as illustrated in FIGS. 19C and 19G; and (iii) if a SL slot includes PSFCH, the length of SL-PRS is such that the last SL-PRS symbol is the second SL symbol before the start of PSFCH, wherein the symbol between the end of SL-PRS and start of PSFCH is a gap symbol (e.g., with no SL transmission), as illustrated in FIGS. 19D and 19H; (3) the ending symbol of SL-PRS in a slot; (4) whether or not SL-PRS is one shot, N-shots or periodic; and (5) the periodicity of SL-PRS across slots.

In one example, information related to frequency domain behavior of SL-PRS can be included. This can include: (1) the starting sub-channel (or PRB or sub-carrier) of SL-PRS; (2) the number of sub-channels (or PRBs or sub-carriers) of SL-PRS; (3) the ending sub-channel (or PRB or sub-carrier) of SL-PRS; (4) Comb size N, wherein N∈{1, 2, 4, 6, 8, 12}. In one example, N=1, i.e., every sub-carrier can be used for the SL positioning reference signal within the frequency domain allocation for SL PRS; and (5) the Comb offset: (i) in one example, the same transmission comb offset is used in all symbols of a slot; (ii) in one example, the transmission combs are fully staggered; and (iii) in one example, the transmission combs are partially staggered. The starting sub-channel or starting PRB or start sub-carrier or ending sub-channel or ending PRB or ending sub-carrier can be a sub-channel number or a PRB number or a sub-carrier number, respectively, within a SL BWP or a SL resource pool used for the transmission of the SL PRS.

In one example, information related to the sequence generation of SL-PRS can be included e.g., hopping type, sequence ID. In one instance, the sequence used for SL-PRS can be based UE's source ID or destination ID (e.g., 12 LSBs or 12 MSBs) or TMSI (Temporary Mobile Subscribed Identity) (e.g., 12 LSBs or 12 MSBs) or IMEI (International Mobile Equipment Identity) (e.g., 12 LSBs or 12 MSBs).

In one example, source and/or destination IDs can be included.

The aforementioned parameters can be included in SCI-P and/or (pre-)configured and/or determined based on system specifications and/or determined based on other fields in SCI format 1-A or a field in the second stage SCI format (e.g., SCI format 2-A, 2-B or 2-C). In one example, if the aforementioned parameters are specified by system specifications and/or (pre-) configured and are then further included in SCI-P. The value of the corresponding parameter in SCI-P can override a system specified or (pre-)configured value.

In one example of FIG. 18 and FIG. 19 , the SCI-P is mapped to PSCCH-like channel, the PSCCH occupies the same PRBs occupied by SL-PRS.

In one example, the PSCCH-like channel can have 2 or 3 symbols after the AGC symbol.

In one example, the PSCCH DMRS occupies 3 REs per PRB (e.g., sub-carriers 1, 5 and 9), i.e., the sub-carriers occupied by PSCCH DMRS can be expressed as k=nN_(sc) ^(RB)+4k′+1, wherein, N_(sc) ^(RB)=12, the number of sub-carriers per PRB, and n is the PRB number and k′=0, 1, 2.

In one example, the PSCCH DMRS occupies 3 REs per PRB i.e., the sub-carriers occupied by PSCCH DMRS can be expressed as k=nN_(sc) ^(RB)+4k′+0, wherein, N_(sc) ^(RB)=12, the number of sub-carriers per PRB, and n is the PRB number and k′=0, 1, 2, 0 can be 0, or 1 or 2 or 3.

In one example of FIG. 18 and FIG. 19 , the SCI-P is mapped to PSSCH-like channel, the PSSCH occupies the same PRBs occupied by SL-PRS.

In one example, the PSSCH-like channel can have 2 or 3 symbols after the AGC symbol.

In one example, the sub-carriers occupied by PSSCH DMRS can be expressed as one of: (1) k=nN_(sc) ^(RB)+4k′+0, wherein, N_(sc) ^(RB)=12, the number of sub-carriers per PRB, and n is the PRB number and k′=0, 1, 2. O can be one of 0 or 1 or 2 or 3. In this example, there are 3 PSSCH DMRS sub-carriers per PRB; (2) k=nN_(sc) ^(RB)+3k′+0, wherein, N_(sc) ^(RB)=12, the number of sub-carriers per PRB, and n is the PRB number and k′=0, 1, 2, 3. O can be one of 0 or 1 or 2. In this example, there are 4 PSSCH DMRS sub-carriers per PRB; (3) k=nN_(sc) ^(RB)+2k′+0, wherein, N_(sc) ^(RB)=12, the number of sub-carriers per PRB, and n is the PRB number and k′=0, 1, 2, 3, 4, 5. O can be one of 0 or 1. In this example, there are 6 PSSCH DMRS sub-carriers per PRB; or (4) k=nN_(sc) ^(RB)+6k′+0, wherein, N_(sc) ^(RB)=12, the number of sub-carriers per PRB, and n is the PRB number and k′=0, 1. O can be one of 0 or 1 or 2 or 3 or 4 or 5. In this example, there are 2 PSSCH DMRS sub-carriers per PRB.

In one example, the number PSSCH symbols is 2 and PSSCH DMRS REs are present in both symbols.

In one example, the number PSSCH symbols is 2 and PSSCH DMRS REs are present in the first symbol only.

In one example, the number PSSCH symbols is 2 and PSSCH DMRS REs are present in the second symbol only.

In one example, the number PSSCH symbols is 3 and PSSCH DMRS REs are present in all symbols.

In one example, the number PSSCH symbols is 3 and PSSCH DMRS REs are present in the first and third symbols only.

In one example, the number PSSCH symbols is 3 and PSSCH DMRS REs are present in the first and second symbols only.

In one example, the number PSSCH symbols is 3 and PSSCH DMRS REs are present in the second and third symbols only.

In one example, the number PSSCH symbols is 3 and PSSCH DMRS REs are present in the first symbol only.

In one example, the number PSSCH symbols is 3 and PSSCH DMRS REs are present in the second symbol only.

In one example, the number PSSCH symbols is 3 and PSSCH DMRS REs are present in the third symbol only.

In one example, the control information associated with the reference signal for SL positioning measurements is transmitted in a separate slot from the slot of the reference signal for SL positioning measurements.

In one example, a sidelink transmission in slot n in includes a PSCCH+PSSCH transmission, wherein the PSCCH transmission includes SCI Format 1-A. SCI Format 1-A is used for signaling/reserving sl-MaxNumPresReserve aperiodic resources. Wherein, sl-MaxNumPresReserve is a higher layer configured parameter that can have a value of 2 or 3. One signaled reserved resources is a PSSCH transmission in the same slot as the PSCCH. This is illustrated in FIG. 20 .

FIG. 20 illustrates an example of control information associated with the reference signal for SL positioning measurements 2000 according to embodiments of the present disclosure. An embodiment of the control information associated with the reference signal for SL positioning measurements 2000 shown in FIG. 20 is for illustration only.

If sl-MaxNumPresReserve is 2, the additional resource reserved by SCI Format 1-A is for a transmission of a SL-PRS (reference signal for positioning measurement on the SL interface).

If sl-MaxNumPresReserve is 3, the two additional resources reserved by SCI Format 1-A are for a transmission of a SL-PRS (reference signal for positioning measurement on the SL interface).

In one example, a sidelink transmission in slot n in includes a PSCCH+PSSCH transmission, wherein the PSCCH transmission includes SCI Format 1-A. SCI Format 1-A is used for signaling/reserving periodic resources based on the field “resource reservation period,” when higher layer parameter sl-MultiReserveResource is configured. Wherein, the “resource reservation period” fields signals a value in list sl-ResourceReservePeriodList. This is illustrated in FIG. 21 .

FIG. 21 illustrates another example of control information associated with the reference signal for SL positioning measurements 2100 according to embodiments of the present disclosure. An embodiment of the control information associated with the reference signal for SL positioning measurements 2100 shown in FIG. 21 is for illustration only.

The SL control information associated with the PRS (denoted as SCI-P) can be included in PSSCH.

In one example, the SCI-P is included in a second stage SCI in PSSCH (e.g., SCI Format 2-D), and there is no addition information multiplexed in PSSCH (i.e., no SL-SCH). SCI Format 2-D can be indicated in the “2nd stage SCI format” field of the first stage SCI format (e.g., SCI format 1-A).

In one example, the SCI-P is included in a second stage SCI in PSSCH (e.g., SCI Format 2-D), and there is a SL-SCH channel that includes a MAC CE that also conveys SCI-P. No additional SL data is multiplexed in the SL-SCH. SCI Format 2-D can be indicated in the “2nd stage SCI format” field of the first stage SCI format (e.g., SCI format 1-A).

In one example, the SCI-P is included in a second stage SCI in PSSCH (e.g., SCI Format 2-D), and there is a SL-SCH channel that includes a MAC CE that also conveys SCI-P, the SL-SCH can also multiplex other SL-data. SCI Format 2-D can be indicated in the “2nd stage SCI format” field of the first stage SCI format (e.g., SCI format 1-A).

In one example, the SCI-P is included in a SL-SCH channel that includes a MAC CE that also conveys SCI-P. No additional SL data is multiplexed in the SL-SCH. In one example, sl-NumReservedBits can be set to 2 or 3 or 4. One or more of the bits (other than the bit used for conflict capability signaling, if configured) is used to indicate that the aperiodic reserved resources and/or the periodic reserved resources (in one example, one of the sl-NumReservedBits can be used for indicating periodic reserved resources, one of the sl-NumReservedBits can be used for indicating aperiodic reserved resources) are used for SL-PRS.

In one example, the SCI-P is included in a SL-SCH channel that includes a MAC CE that also conveys SCI-P, the SL-SCH can also multiplex other SL-data. One or more of the bits (other than the bit used for conflict capability signaling, if configured) is used to indicate that the aperiodic reserved resources and/or the periodic reserved resources (in one example, one of the sl-NumReservedBits can be used for indicating periodic reserved resources, one of the sl-NumReservedBits can be used for indicating aperiodic reserved resources) are used for SL-PRS.

In one example, the SCI-P can include one or more of the following examples.

FIGS. 22A-22H illustrate examples of time domain information 2200 according to embodiments of the present disclosure. An embodiment of the time domain information 2200 shown in FIGS. 22A-22H is for illustration only.

In one example, information related to time domain behavior of SL-PRS can be included. This can include: (1) the starting symbol of SL-PRS in a slot. In one example, the starting symbol of SL-PRS in a slot is signaled. In one example, the SL-PRS starts in the first SL symbol of a slot, and is not signaled in SCI-P, as illustrated in FIGS. 22A, 22B, 22C, and 22D. In one example, the SL-PRS starts in the second SL symbol of a slot, and is not signaled in SCI-P, wherein the first SL symbol of a slot is a duplicate symbol (e.g., AGC symbol) for the first symbol of SL-PRS, as illustrated in FIGS. 22E, 22F, 22G, and 22H; (2) the length in symbols of SL-PRS within a slot. In one example, the length of SL-PRS within a slot is signaled. In one example, the length of SL-PRS is not signaled in SCI-P, and one of the following: (i) the length of SL-PRS is such that the last SL-PRS symbol is the last SL symbol a slot, as illustrated in FIGS. 22A and 22E; (ii) the length of SL-PRS is such that the last SL-PRS symbol is the second from last SL symbol a slot, wherein the last SL symbol of slot is a gap symbol (e.g., with no SL transmission), as illustrated in FIGS. 22B and 22F; (iii) if a SL slot includes PSFCH, the length of SL-PRS is such that the last SL-PRS symbol is the SL symbol before the start of PSFCH, as illustrated in FIGS. 22C and 22G; and/or (iv) if a SL slot includes PSFCH, the length of SL-PRS is such that the last SL-PRS symbol is the second SL symbol before the start of PSFCH, wherein the symbol between the end of SL-PRS and start of PSFCH is a gap symbol (e.g., with no SL transmission), as illustrated in FIGS. 22D and 22H; (3) the ending symbol of SL-PRS in a slot; (4) whether or not SL-PRS is one shot, N-shots or periodic; and (5) the periodicity of SL-PRS across slots.

In one example, information related to frequency domain behavior of SL-PRS can be included. This can include: (1) the starting sub-channel (or PRB or sub-carrier) of SL-PRS; (2) the number of sub-channels (or PRBs or sub-carriers) of SL-PRS; (3) the ending sub-channel (or PRB or sub-carrier) of SL-PRS; (4) Comb size N, wherein N∈{1, 2, 4, 6, 8, 12}. In one example, N=1, i.e., every sub-carrier can be used for the SL positioning reference signal within the frequency domain allocation for SL PRS; and (5) The Comb offset: (i) in one example, the same transmission comb offset is used in all symbols of a slot; (ii) in one example, the transmission combs are fully staggered; and (iii) in one example, the transmission combs are partially staggered. The starting sub-channel or starting PRB or start sub-carrier or ending sub-channel or ending PRB or ending sub-carrier can be a sub-channel number or a PRB number or a sub-carrier number, respectively, within a SL BWP or a SL resource pool used for the transmission of the SL PRS.

In one example, information related to the sequence generation of SL-PRS can be included, e.g., hopping type, sequence ID. In one example, the sequence used for SL-PRS can be based UE's source ID or destination ID (e.g., 12 LSBs or 12 MSBs) or a temporary mobile subscribed identity (TMSI) (e.g., 12 LSBs or 12 MSBs) or an international mobile equipment identity (IMEI) (e.g., 12 LSBs or 12 MSBs).

In one example, source and/or destination IDs can be included.

The aforementioned parameters can be included in SCI-P and/or (pre-)configured and/or determined based on system specifications and/or determined based on other fields in SCI format 1-A or a field in the second stage SCI format (e.g., SCI format 2-A, 2-B or 2-C). In one example, if the aforementioned parameters are specified by system specifications and/or (pre-)configured and are then further included in SCI-P. The value of the corresponding parameter in SCI-P can override a system specified or (pre-)configured value.

The present disclosure can be applicable to Rel-18 NR specifications for sidelink positioning.

SL is one of the promising features of NR, targeting verticals such the automotive industry, public safety, industrial internet of things (IIoT) and other commercial application. SL has been first introduced to NR in release 16, with emphasis on V2X and public safety where the requirements are met. The support of SL has been expanded to other types of UEs such a vulnerable road users (VRUs), pedestrian UEs (PUEs) and other types of hand held devices, by supporting mechanisms for power saving for SL resource allocation as well as mechanisms that enhance reliability and reduce latency of SL transmissions.

Another feature that NR supports is positioning, using the NR radio interface for performing positioning measurements to determine or assist in determining the location of a UE. NR positioning was first introduced using the Uu interface in Rel-16, and further enhanced for improved accuracy and reduced latency in Rel-17. In Rel-18 a new study item has been approved to study and evaluate performance and feasibility of potential solutions for SL positioning. In this disclosure the content of signaling information associated with SL PRS is considered.

The above flowcharts illustrate example methods that can be implemented in accordance with the principles of the present disclosure and various changes could be made to the methods illustrated in the flowcharts herein. For example, while shown as a series of steps, various steps in each figure could overlap, occur in parallel, occur in a different order, or occur multiple times. In another example, steps may be omitted or replaced by other steps.

Although the present disclosure has been described with exemplary embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims. None of the description in this application should be read as implying that any particular element, step, or function is an essential element that must be included in the claims scope. The scope of patented subject matter is defined by the claims. 

What is claimed is:
 1. A user equipment (UE) comprising: a transceiver configured to receive configuration information for a sidelink (SL) resource pool, wherein the SL resource pool is used for SL positioning reference signal (PRS) and control information associated with the SL PRS; and a processor operably coupled to the transceiver, the processor configured to determine, based at least on the configuration information, resources for the SL PRS from the SL resource pool, wherein the transceiver is further configured to: transmit the control information associated with the SL PRS, and transmit the SL PRS on the determined resources.
 2. The UE of claim 1, wherein: the control information associated with the SL PRS and the SL PRS are transmitted in a same SL slot, and the control information is transmitted in a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH).
 3. The UE of claim 1, wherein a guard symbol is included after the SL PRS.
 4. The UE of claim 1, wherein the processor is further configured to perform sensing to determine the resources for the SL PRS from the resource pool.
 5. The UE of claim 1, wherein: the control information associated with the SL PRS includes a comb offset index, and a comb offset used within a SL PRS symbol is based on an index of the SL PRS symbol and the comb offset index.
 6. The UE of claim 1, wherein the control information associated with the SL PRS includes a starting sub-channel for the SL PRS in the resource pool and a number of consecutive sub-channels for the SL PRS.
 7. The UE of claim 1, wherein the control information associated with the SL PRS includes a starting symbol within a slot for the SL PRS and a number of consecutive symbols for the SL PRS.
 8. A user equipment (UE) comprising: a transceiver configured to: receive configuration information for a sidelink (SL) resource pool, wherein the SL resource pool is used for a SL positioning reference signal (PRS) and control information associated with the SL PRS, receive the control information associated with the SL PRS, and receive the SL PRS based on the control information; and a processor operably coupled to the transceiver, the processor configured to: perform a positioning measurement based on the SL PRS, and determine a positioning measurement report based on the positioning measurement, wherein the transceiver is further configured to transmit the positioning measurement report.
 9. The UE of claim 8, wherein: the control information associated with the SL PRS and the SL PRS are received in a same slot, and the control information is received in a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH).
 10. The UE of claim 8, wherein a guard symbol is included after the SL PRS.
 11. The UE of claim 8, wherein: the control information associated with the SL PRS includes a comb offset index, and a comb offset used within a SL PRS symbol is based on an index of the SL PRS symbol and the comb offset index.
 12. The UE of claim 8, wherein the control information associated with the SL PRS includes a starting sub-channel for the SL PRS in the resource pool and a number of consecutive sub-channels for the SL PRS.
 13. The UE of claim 8, wherein the control information associated with the SL PRS includes a starting symbol within a slot for the SL PRS and a number of consecutive symbols for the SL PRS.
 14. A method of operating a user equipment (UE), the method comprising: receiving configuration information for a sidelink (SL) resource pool, wherein the SL resource pool is used for a SL positioning reference signal (PRS) and control information associated with the SL PRS; determining, based at least on the configuration information, resources for the SL PRS from the SL resource pool; transmitting the control information associated with the SL PRS; and transmitting the SL PRS on the determined resources.
 15. The method of claim 14, wherein: the control information associated with the SL PRS and the SL PRS are transmitted in a same SL slot, and the control information is transmitted in a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH).
 16. The method of claim 14, wherein a guard symbol is included after the SL PRS.
 17. The method of claim 14, further comprising performing sensing to determine the resources for the SL PRS from the resource pool.
 18. The method of claim 14, wherein: the control information associated with the SL PRS includes a comb offset index, and a comb offset used within a SL PRS symbol is based on an index of the SL PRS symbol and the comb offset index.
 19. The method of claim 14, wherein the control information associated with the SL PRS includes a starting sub-channel for the SL PRS in the resource pool and a number of consecutive sub-channels for the SL PRS.
 20. The method of claim 14, wherein the control information associated with the SL PRS includes a starting symbol within a slot for the SL PRS and a number of consecutive symbols for the SL PRS. 